Medication injector apparatus with drive assembly that facilitates reset

ABSTRACT

A medication injector apparatus such as an injection pen. The injection pen includes a resettable, cartridge plunger drive assembly including an axially floating nut, a cartridge plunger engaging screw, and a drive clutch movable with the nut and which when rotated causes the screw to screw through the nut. When a cartridge assembly is mounted to the pen base, the floating nut and drive clutch are shifted proximally such that the drive clutch is in torque transmitting engagement with a rotatable drive member of the pen, such that rotation of that drive member results in drive screw advancement through the nut in the distal direction. The injection pen also may include an injection clicker assembly having a collar arranged coaxially on a drive sleeve and which oscillates axially on the drive sleeve that rotates during medication dispensing to provide an audible clicking sound that indicates injecting use of the pen.

This application is a divisional of Ser. No. 10/477,781 filed May 28,2004, now U.S. Pat. No. 7,195,616, which was a §371 national applicationof PCT/US02/11876 filed May 8, 2002, which claims the benefit ofProvisional Application Nos. 60/291,437 filed May 16, 2001; 60/297,051filed Jun. 8, 2001; 60/303,613 filed Jul. 6, 2001; and 60/324,199 filedSep. 21, 2001.

BACKGROUND OF THE INVENTION

The present invention pertains to medication delivery devices, and, inparticular, to portable medication delivery devices such as injectionpens.

Patients suffering from a variety of diseases, such as diabetes,frequently must inject themselves with medication, such as insulinsolutions. To permit a person to conveniently and accuratelyself-administer proper doses of medicine, a variety of devices broadlyknown as injector pens or injection pens have been developed.

In order to permit a person to administer a proper dose, injection penshave been equipped with a wide variety of dosing and injectingmechanisms that enable a particular dosage to be conveniently selectedand then dispensed. Generally, these pens are equipped with a cartridgeincluding a plunger and containing a multi-dose quantity of liquidmedication. A drive member is movable forward to advance the plunger inthe cartridge in such a manner to dispense the contained medication fromthe opposite cartridge end, typically through a needle that penetrates astopper at that opposite end. In reusable pens, after the pen has beenutilized to exhaust the supply of medication within the cartridge, auser can remove and dispose of the spent cartridge. Then, to prepare forthe next cartridge, the plunger-engaging drive member of the pen isreset to its initial position, either manually or automatically duringattachment of a replacement cartridge, and the injection pen can then beused to the exhaustion of that next cartridge.

In order to allow the reset of the plunger-engaging drive member ofreusable injection pens, a variety of assemblies have been utilized. Oneknown assembly utilizes a nut fixed within the housing, such as byultrasonic welding, which nut threadedly engages a drive screw that whenrotated is extendable from the base of the injection pen to advance theplunger of a cartridge within a retainer mounted to the pen base.Rotation of the drive screw to screw it through the fixed nut to advancethe plunger is effected by a toothed drive clutch, keyed to rotate withthe screw, which engages a toothed drive member that rotates duringoperation of the injecting mechanism. The drive clutch, which is forcedinto torque transmitting relationship with the drive member when thecartridge retainer is mounted to the pen base, is spring biased awayfrom the toothed drive member when the cartridge retainer is removed.While effective to advance the drive screw, and to allow that screw tobe reset or pushed back into the pen base during the process of mountingthe cartridge retainer, this assembly is not without its shortcomings.For example, due to the relatively large size of the drive clutch, aflywheel effect of the rotating clutch during screw resetting may causethe screw to retract so far that the initial priming of the pen may beinconvenient to perform.

Injection pens have been equipped with an assortment of mechanisms thatgenerate an audible clicking noise during the injecting process. Thisclicking noise is intended to inform a user that the pen is operating toadminister medication. One known pen uses an injection clicker mechanismwhich employs a series of radially extending leaf springs arrangedaround the periphery of a disk-shaped, radially projecting portion of adrive sleeve of the injecting mechanism. As the injecting mechanism ofthe pen is operated, the drive sleeve rotates, causing rotation of aclutch that has been axially moved during pen assembly so as to beengaged by teeth that axially extend in the distal direction from thedrive sleeve radially projecting portion. As the clutch rotates, a drivescrew that extends through the drive sleeve and to which the clutch iskeyed is caused to rotate, and the drive screw advances axially as itscrews through a nut within the pen housing to move a cartridge plungerand expel medicine from the pen. During the drive sleeve rotation, theradially extending leaf springs arranged around the drive sleeveradially projecting portion slip into and out of recesses in the penhousing located radially outward thereof, thereby producing audibleclicking noises associated with injection. The leaf springs, wheninserted in the housing recesses when drive sleeve rotation is halted,are designed to prevent counter-rotation of the drive sleeve which wouldallow undesirable back up of the drive screw. While useful, thisinjection clicker design is not without its shortcomings. For example,modifying the feel and sound of the injection clicks during the designof the pen may involve modifications to the mold cavities of thehousing. Still further, the radially extending leaf springs mayundesirably increase the overall girth of the injection pen.

In another injection pen disclosed in U.S. Pat. No. 5,688,251, aninjection clicker is provided by a spring biased distal clutch withaxially facing teeth which is coaxially arranged on and splined to a nutthat engages an advanceable lead screw. The spring that pushes thedistal clutch teeth against the housing bulkhead to create audibleclicking during injection also pushes a proximal clutch against a driverto create audible feedback during dose dialing. While perhapsfunctional, this design is not without its shortcomings. For example,because the spring used within the injection audible feedback design isalso used as part of the dialing audible feedback design, the injectionaudible feedback cannot be tuned or adjusted by modifying that springwithout also affecting the dialing audible feedback, and potentiallyother features such as dialing torque.

Another limitation of reusable injection pens is that because differenttypes of medicines, provided in separate cartridges, possibly may beutilized with the same reusable pen body, a user of the injection penand those various cartridges needs to be vigilant to ensure the pen isused to administer the correct dosage of medicine. In order to assist auser in identifying medicine contained in a cartridge, a cartridgerecognition system has previously been disclosed in U.S. Pat. No.5,954,700. In that system, a medicine-filled cartridge includes aninformation providing source designed to provide information regardingthe cartridge to the electronic delivery device, such as an injectionpen for which it is adapted. While useful, the information provided doesnot necessarily result in the delivery device indicating to a user theactual dose of medicine being administered by the delivery device, andcalculation errors on the part of the user are possible, resulting inincorrect doses.

Another limitation of some injection pens relates to the dose settingmechanism. One mechanism disclosed in U.S. Pat. No. 5,509,905 includesswitches that are used in forming signals when the switches are actuatedduring rotation by a user of an operating head extending from the penbase. The signals are used in mathematically establishing the number ofunit volumes set by the user. However, the use of cams to activate theswitches results in the resistance to rotating the operating headnoticeably varying during revolution of that operating head.

Another problem with some existing injection pens is that dosing andinjecting operations of the pen are not intuitive to all users. Inparticular, with some pens, the user first must rotate a knob of the pento set the medicine dose to be delivered as indicated by numbers on amarked dial fixedly connected with the knob, and then must apply anaxial or plunging force which moves the knob axially to inject themedicine dose. Because for some pen designs the knob and dial will haveaxially translated away from the pen base while being rotated duringdose setting, and further that knob and dial, when plunged duringinjecting, will also rotate back into the pen base so as to provide viaits markings a continuous indication of the amount of medicine remainingto be delivered, a user may come to believe that rotating down theproximally extended knob will inject the medicine. However, such abelief is erroneous for at least one pen design, and therefore a userwho operates under such an erroneous belief may not properlyself-administer the desired medicine.

In a well known disposable injection pen design, a dose is similarly setby rotating out a knob, connected to a number-marked dial, such that thedial translates out while rotating. While the dial is rotated, asequence of numbers helically arranged on the dial is visible through aviewing window to show the dose the pen is then set to deliver. In thisdesign, application of a plunging force moves the knob and the dialaxially and without rotation to inject the medicine dose. However, whileuseful, this design is not without its shortcomings. For one thing,during plunging, few if any of the dose-indicating numbers which havebeen passed in setting the pen are displayed, which may be a source ofconfusion for some users. Furthermore, after the pen is used forinjecting, the dial has to be reset before it can be screwed outward toset the next dose for delivery. Resetting requires a rotation of thedial to a zero position, except for a limited number of dose quantitiespreviously injected, followed by an axial shifting of the dial.

Thus, it would be desirable to provide a device or method that overcomesone or more of these and other shortcomings of the prior art.

BRIEF SUMMARY OF THE INVENTION

The present invention encompasses a drive assembly that is operable toadvance a plunger of a cartridge of a portable injector apparatus suchas an injection pen, and which is resettable with minimal effort duringreplacement of the spent cartridge.

The present invention also encompasses an assembly within a portableinjector apparatus that during dose injecting provides to a user anaudible indication of operation, which audible indication is readilyadjustable by the manufacturer by, for example, a substitution ofbiasing elements.

The present invention also encompasses a therapeutic dose indicatingapparatus for a medicine delivery device, such as an injection pen,which first determines a therapeutic dose based on a sensed medicineconcentration and a sensed dose volume setting, and then visiblydisplays the determined therapeutic dose. The invention furtherencompasses a doseable quantity identifier for an injection pen whichuses a sensor, such as with electrical contacts, to read a matrix todetermine how a dose setting mechanism has been rotationally arranged bya user in setting the pen for dose administration.

The present invention also encompasses a medication injector apparatusincluding an assembly for selectively rotating a drive sleeve, whichassembly has a dial that rotates out during dose setting and whichtranslates in without rotation during dose injecting. The dial is keyedto a barrel within the apparatus, and further is threadedly engaged withthe drive sleeve that is operably connected to a drive memberadvanceable to force medication from a fluid container within theapparatus. The relative rotation experienced by the barrel and drivesleeve during dosing and injecting is used by an electrical sensingmechanism in recognizing the arrangement of the apparatus for thepurpose of displaying to a user the dose selected and remaining to beinjected.

In one form thereof, the present invention provides a resettable,cartridge plunger drive assembly of a dose injecting mechanism of amedication injector apparatus which has a reusable base and a cartridgeassembly mountable thereto. The base has a rotatable drive member of thedose injecting mechanism within its housing, and the cartridge assemblyhas a medicine-filled cartridge with a movable plunger at one end and anoutlet at the other end. The drive assembly includes a nut, a screw, adrive clutch, and a biasing element. The nut is keyed to the basehousing to be both movable relative thereto between first and secondaxial positions, and rotatably fixed relative thereto at the first andsecond axial positions. The screw includes a plunger-engaging distal endand external threading in threaded engagement with an internallythreaded opening of the nut. The drive clutch is connected to the nut tobe axially retained and rotatably movable relative thereto. The driveclutch is keyed to the screw to be rotatably fixed and axially movablerelative thereto. The nut is positioned within the base housing to beaxially movable from the first axial position to the second axialposition by engagement with the cartridge assembly during mounting ofthe cartridge assembly to the reusable base. The drive clutch is intorque transmitting engagement with the rotatable drive member when thenut is disposed in the second axial position, whereby rotation of thedrive member during operation of the dose injecting mechanism rotatesthe drive clutch and thereby the screw to produce axial movement of thescrew in a distal direction through the nut to thereby advance theplunger-engaging distal end of tile screw to force medication from thecartridge outlet. The biasing element biases the nut from the secondaxial position toward the first axial position when the cartridgeassembly is not mounted to the reusable base. The drive clutch isdisengaged from torque transmitting engagement with the rotatable drivemember when the nut is disposed in the first axial position, wherebyapplication of a force in a proximal direction on the plunger-engagingdistal end of the screw axially moves the screw in a proximal directionas it screws through the nut to thereby reset the screw.

In another form thereof, the present invention provides a resettable,cartridge plunger drive assembly of a dose injecting mechanism of amedication injector apparatus which has a reusable base and a cartridgeassembly mountable to the base. The apparatus base has a rotatable drivemember of the dose injecting mechanism within its housing, and thecartridge assembly has a medicine-filled cartridge with a movableplunger at one end and an outlet at the other end. The drive assemblyincludes a nut, a screw, a drive clutch, and a biasing element. The nutis keyed to the base housing to be both movable relative thereto betweenfirst and second axial positions, and rotatably fixed relative theretoat the first and second axial positions. The screw includes aplunger-engaging distal end and external threading in threadedengagement with an internally threaded opening of the nut. The driveclutch is keyed to the screw to be rotatably fixed and axially movablerelative thereto. The nut is positioned within the base housing to beaxially movable from the first axial position to the second axialposition by engagement with the cartridge assembly during mounting ofthe cartridge assembly to the reusable base. The drive clutch isstructured and arranged to be shifted from a location out of torquetransmitting engagement with the rotatable drive member to a location intorque transmitting engagement with the rotatable drive member when thenut is moved from the first axial position to the second axial position,wherein when the drive clutch is in torque transmitting engagement withthe rotatable drive member, rotation of the drive member duringoperation of the dose injecting mechanism rotates the drive clutch andthereby the screw to produce axial movement of the screw in a distaldirection through the nut to thereby advance the plunger-engaging distalend of the screw to force medication from the cartridge outlet. Thebiasing element is structured and arranged to bias the drive clutch fromthe location in torque transmitting engagement with the rotatable drivemember to the location out of torque transmitting engagement with therotatable drive member, and thereby move the nut from the second axialposition toward the first axial position, when the cartridge is notmounted to the reusable apparatus base, wherein when the drive clutch isout of torque transmitting engagement with the rotatable drive member,application of a force in a proximal direction on the plunger-engagingdistal end of the screw axially moves the screw in a proximal directionas it screws through the nut to thereby reset the screw.

In another form thereof, the present invention provides an injectionclicker assembly of a medication injector apparatus, which apparatusincludes a drive screw advanceable in a distal direction to shift amovable plunger of a cartridge so as to force medication from an outletof the cartridge, a drive sleeve of a dose injecting mechanism rotatablein a first direction within a housing of the apparatus, the drive sleeveincluding a distal facing surface and defining a longitudinal bore inwhich the drive screw extends, and a clutch, connected to the drivescrew, that is rotated by engagement with the drive sleeve distal facingsurface to thereby rotate and advance the drive screw through a nutwithin the housing. The injection clicker assembly includes a collararranged coaxially on the drive sleeve at a location proximal of thedistal facing surface of the drive sleeve. The collar is connected tothe drive sleeve to be axially movable relative thereto and rotatablyfixed thereto when the drive sleeve rotates in the first direction. Thecollar includes a plurality of teeth extending in an axial direction andadapted to engage mating teeth of a stop surface one of integrallyformed with and non-rotatably connected to a housing of the apparatus.The injection clicker assembly also includes a biasing element adaptedto force the collar axially into meshing engagement with the stopsurface. The collar and the stop surface are complementarily configuredsuch that during rotation of the drive sleeve in the first direction,and due to a returning force applied to the collar by the biasingelement, the collar oscillates axially on the drive sleeve as the collarteeth slide over the stop surface teeth to provide an audible clickingsound that indicates injecting use of the apparatus.

In another form thereof, the present invention provides a therapeuticdose indicating apparatus for a portable medication injector devicewhich includes an adjustable dose setting mechanism and which is loadedwith a replaceable medicine container. The apparatus includes a visibledisplay, a container recognizer that recognizes a concentration ofmedicine within the container, which container recognizer includes anidentifier disposed on the container, a doseable quantity identifierthat identifies a volume of medicine selected for delivery by theadjustable dose setting mechanism, and a controller adapted to determinea therapeutic dose based on the recognized concentration and theidentified volume and cause the therapeutic dose to be displayed in thevisible display.

In another form thereof, the present invention provides a doseablequantity identifier for a medication injector apparatus having a dosesetting mechanism operable to select a volume of medicine to bedelivered from a held cartridge. The doseable quantity identifierincludes a rotational matrix disposed on a first component of theapparatus, a sensor for electrically sensing the rotational matrix,which sensor is disposed on a second component of the apparatus whichexperiences rotational motion relative to the first component duringoperation of the dose setting mechanism, whereby data of the rotationalmatrix sensible by the matrix sensor is thereby indicative of anarrangement of the dose, setting mechanism, a controller circuited withthe sensor which interprets data of the rotational matrix sensed by thesensor to determine a quantity of medicine to be delivered from thecartridge during injection, and a visible display that displays thequantity of medicine to be delivered as determined by the controller.

In still another form thereof, the present invention provides a methodof indicating a therapeutic dose to a user of a portable medicationinjector apparatus loaded with a cartridge of medicine, the portablemedication injector apparatus including a dose setting mechanismoperable to select a volume of medicine for delivery. The methodincludes the steps of recognizing a concentration of the medicine withinthe cartridge with a cartridge recognizer of the portable medicationinjector apparatus, identifying a selected delivery volume with adoseable quantity identifier of the portable medication injectorapparatus, determining the therapeutic dose with a controller of theportable medication injector apparatus using the recognizedconcentration and the identified selected delivery volume as input, anddisplaying the determined therapeutic dose on a display of the portablemedication injector apparatus.

In still another form thereof, the present invention provides amedication injector apparatus comprising a housing, a fluid containermounted to the housing defining a medicine-filled reservoir andincluding a movable piston at a proximal end of the reservoir, a needleassembly removably attached to a distal end of the fluid container tohave an injection needle of the needle assembly in flow communicationwith the reservoir, a drive member advanceable within the housing in adistal direction to move the piston toward the injection needle forforcing medicine from the container, and a dose setting element thatincludes a control portion external to the housing and manuallyrotatable in a first direction to screw the dose setting element from aplunged position to a plungeable position at which the dose settingelement projects farther proximally from the housing than at the plungedposition. The apparatus also includes means, operable by translatingwithout rotation the dose setting element from the plungeable positionto the plunged position, for advancing the drive member in the distaldirection, the advancing means comprising a drive sleeve and a barrelwithin the housing that experience relative rotation during at least aportion of a movement of the dose setting element between the plungedposition and the plungeable position, and an electronics assembly thatdisplays a dose of medicine to be injected based on a sensing of therelative rotational positions of the barrel and the drive sleeve.

In still another form thereof, the present invention provides amedication injector apparatus including a housing, a medicine-filledcontainer mounted to the housing and including a movable piston at oneend and an outlet at the other end, a drive member advanceable withinthe housing in a distal direction to move the piston toward the outletfor forcing medicine from the container, a drive sleeve around andoperatively connected to the drive member, which drive sleeve isrotatable to advance the drive member distally, a barrel around thedrive sleeve and movable in the distal direction within the housing byengagement with the drive sleeve from a first axial position to a secondaxial position, which barrel is freely rotatable relative to the housingat the first axial position and rotatably fixed relative to the housingat the second axial position, a dose setting element including amanually rotatable portion external to the housing, which dose settingelement is keyed with the barrel within the housing to be axiallymovable and rotatably fixed relative to the barrel, and which is inthreaded engagement with the drive sleeve. The manually rotatableportion is rotatable in a first direction such that the dose settingelement rotates and moves proximally along the drive sleeve due to thethreaded engagement therebetween, whereby the dose setting element movesfrom a plunged position to a plungeable position at which the dosesetting element projects farther proximally from the housing than at theplunged position. When the dose setting element is in the plungeableposition, application of a force in a distal direction on the dosesetting element first translates distally and without rotation the dosesetting element and the drive sleeve and the barrel relative to thehousing until the barrel shifts from the first axial position to thesecond axial position, and then, until the dose setting element reachesthe plunged position, translates distally and without rotation the dosesetting element relative to the housing while thereby rotating withouttranslation the drive sleeve to advance the drive member distally withinthe housing.

One advantage of the present invention is that a drive assembly can beprovided which facilitates reset of an injection pen during installationof a replacement medication cartridge.

Another advantage of the present invention is that a drive assembly canbe provided which, without increasing the injection force of theinjection pen in which it is used, allows for a biasing element strongenough to force the drive clutch out of engagement with the drivemember, thereby avoiding a problem found in the prior art in which amore weakly biased drive clutch could bind to the drive member so as tolock the drive screw and prevent reset.

Another advantage of the present invention is that a drive assembly canbe provided which has a relatively small drive clutch to limit flywheeleffects during drive screw reset, which in turn may reduce primingvolumes.

Another advantage of the present invention is that a drive assembly canbe provided which engages a cartridge assembly during its mounting tothe pen base so as to reduce play between the cartridge assembly and thepen base, thereby providing an improved fit therebetween and improvedquality feel to the injection pen.

Another advantage of the present invention is that a drive assembly witha relatively simple design can be provided to reduce costs of assemblyand manufacture.

Another advantage of the present invention is that a drive assembly canbe provided which in one embodiment spring biases forward a loadedcartridge to hold it in place against a forward stop of the holder orretainer of the cartridge assembly to ensure a stable platform for dosedelivery.

Another advantage of the present invention is that a drive assembly canbe provided which in one embodiment is biased together with a loadedcartridge so as to limit relative movement of the cartridge and thedrive screw which otherwise could cause drooling of the pen.

Still another advantage of the present invention is that an injectionclicker assembly can be provided that generates an audible indication toa user of injecting operation of the portable injector in which it isinstalled.

Still another advantage of the present invention is that an injectionclicker assembly can be provided that is readily tunable duringmanufacturing design, such as by altering a spring constant or preloadof a biasing element, to provide the desired tone and loudness of theinjection audible feedback.

Still another advantage of the present invention is that an injectionclicker assembly can be provided that can be tuned during manufactureindependently of any dialing audible feedback or dialing torque of a penin which it is installed.

Still another advantage of the present invention is that an injectionclicker assembly can be provided that can be designed to serve as ananti-backup mechanism for an advanceable drive screw.

Still another advantage of the present invention is that an injectionclicker assembly can be provided that is structured and arranged toutilize space efficiently so as to not adversely impact the length orgirth of the pen in which it is installed.

Still another advantage of the present invention is that an injectionpen can be provided which electronically displays the dose oftherapeutic agent the user has selected for administration by operationof the dose setting mechanism of the pen.

Still another advantage of the present invention is that because thetherapeutic dose displayed is a medically important, actual amount ofmedicine to be administered, rather than a number of clicks or injectionpen unit volumes, a user need not make mental calculations regardingdosing which may be subject to error.

Still another advantage of the present invention is that an injectionpen can be provided which can be used with various types of medicineswhile allowing the pen to display dose information related to theparticular type, such as strength of concentration, of medicine in use.

Still another advantage of the present invention is that a dose that canbe displayed by the injection pen can be determined by the pen after itautomatically recognizes the concentration of the contents of a loadedmedicine container.

Still another advantage of the present invention is that a rotationalmatrix that can be used to determine the selected dose volume permits aunique signal for a small, such as fifteen degree, rotational positionof the dose setting mechanism, has a compact design to fit within asmall physical envelope, and provides a low friction contact solutionfor dose sensing which does not detract from the ease of operation.

Still another advantage of the present invention is that a rotationalmatrix can be provided with a feature that enables the microcontrollerof the apparatus to determine if an invalid sensed matrix position codeshould be ignored as an aberration rather than causing the apparatus toimmediately display an error message.

Yet another advantage of the present invention is that a medicineinjector apparatus can be provided including an assembly for selectivelyrotating a drive sleeve which has different modes of operation duringdose setting and injecting to allow a user to conceptually distinguishbetween the different stages of apparatus use.

Yet another advantage of the present invention is that a medicineinjector apparatus can be provided including an assembly for selectivelyrotating a drive sleeve which includes a dial that rotates whiletranslating during the dose setting operation, yet which translateswithout rotating during the dose injecting operation.

Yet another advantage of the present invention is that a medicineinjector apparatus can be provided including an assembly for selectivelyrotating a drive sleeve which during its injecting operationautomatically resets the apparatus to a zero position from which itsdial can be rotated outward to set the next dose for delivery.

Yet another advantage of the present invention is that a medicineinjector apparatus can be provided including a switch within the housingand used in controlling the electronics of the apparatus, such assetting date and time values.

Yet another advantage of the present invention is that the switch thatcan be provided in the medicine injector apparatus is activated by axialmotion of a component within the housing during use, and serves todistinguish between dosing and injecting operations, which among otherthings makes the switch suitable for triggering a last dose memoryfunction of the pen.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other advantages and objects of this invention,and the manner of attaining them, will become more apparent, and theinvention itself will be better understood, by reference to thefollowing description of embodiments of the invention taking inconjunction with the accompanying drawings, wherein:

FIG. 1 is a diagrammatic plan view of a medicine injection pen equippedwith one form of a dose injecting mechanism including a resettable,cartridge plunger drive assembly of the present invention;

FIG. 2 is a plan view in partial cross-section diagrammatically showingthe injection pen of FIG. 1 prior to the mounting of the cartridgeassembly to the reusable pen base, and with the drive screw of the driveassembly projecting from the distal end of the pen base;

FIG. 3 is a fragmentary plan view in cross-section diagrammaticallyshowing the reusable pen base of FIG. 2;

FIG. 4 is a fragmentary plan view in cross-section diagrammaticallyshowing the injection pen of FIG. 1 with the cartridge assembly fullymounted to the reusable pen base;

FIG. 5 is a perspective view of the drive assembly, and a rotatabledrive member that powers drive assembly operation, removed from theinjection pen of FIG. 1;

FIG. 6 is a cross-sectional view in exploded form of an injection nutand drive clutch of a drive assembly of the present invention;

FIG. 7 is a fragmentary plan view in cross-section diagrammaticallyshowing another injection pen in which an inventive drive assemblybiases forward a cartridge within a retainer mountable to the pen base;

FIG. 8 is a fragmentary view in cross-section diagrammatically showingportions of an injection pen equipped with one form of an injectionclicker assembly of the present invention;

FIG. 9 is a fragmentary view in cross-section diagrammatically showinganother form of an injection clicker assembly of the present inventionwithin portions of another injection pen;

FIG. 10 is an exploded perspective view of the injection clickerassembly of FIG. 9 and portions of the injecting mechanism with which itinteracts;

FIG. 11 is an opposite perspective view of FIG. 10;

FIG. 12 is a block diagram representation of one form of a therapeuticdose indicating apparatus of the present invention;

FIG. 13 is a diagrammatic plan view of an injection pen as the deliverydevice equipped with one form of the therapeutic dose indicatingapparatus shown in FIG. 12;

FIG. 14 is a cross-sectional view of a cartridge assembly removed fromthe injection pen of FIG. 13;

FIG. 15 is a plan view of a first embodiment of a barrel hub of thecartridge assembly of FIG. 14;

FIG. 16 is a plan view of a second embodiment of a barrel hub of thecartridge assembly of FIG. 14;

FIG. 17 is a plan view of a third embodiment of a barrel hub of thecartridge assembly of FIG. 14;

FIG. 18 is a schematic representation of how one form of the therapeuticdose indicating apparatus of the present invention operates;

FIG. 19 is a diagrammatic plan view in partial cross-section of a sensorarray and a dial-mounted rotational matrix of one form of a doseablequantity identifier of the present invention;

FIG. 20 is a plan view of the rotational matrix of FIG. 19 shownunwrapped and removed from the dose setting dial;

FIG. 21 is a plan view of the sensor array removed from the dial-mountedmatrix of FIG. 19, wherein the sensor contacts are shown in dashedlines;

FIG. 22 is a plan view of another embodiment of a doseable quantityidentifier of the present invention;

FIG. 23 is a top view of one form of an injection pen of the presentinvention equipped with an assembly for selectively rotating a drivesleeve to inject a set dose;

FIG. 24 is a cross-sectional front view of the injection pen of FIG. 23prior to the dose setting knob being manually rotated out to set thedose to be delivered by further operation of the injection pen;

FIG. 25 is a cross-sectional view conceptually similar to the view ofFIG. 24 after the cap has been removed, the pen is in a primed state,and the dose setting knob has been rotated out to set the dose fordelivery;

FIG. 26 is a cross-sectional view conceptually similar to the view ofFIG. 25 after the dose setting knob has been slightly plunged so as tomechanically transition the pen to a dose injecting state;

FIG. 27 is an exploded rear perspective view of the injection pen ofFIG. 23;

FIG. 28 is a front perspective view of the slider assembly of FIG. 27;

FIG. 29 is another rear perspective view of the contact assemblies ofFIG. 27; and

FIG. 30 is a plan view of the rotational matrix of FIG. 27 shownunwrapped and removed from the rest of the injection pen.

Corresponding reference characters indicate corresponding partsthroughout the several views. Although the drawings representembodiments of the present invention, the drawings are not necessarilyto scale, and certain features may be exaggerated or omitted in some ofthe drawings in order to better illustrate and explain the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 generally illustrates one type of medication delivery device inwhich a drive assembly of the present invention finds beneficialapplication. The shown delivery device is a reusable, medicationinjection pen, generally designated 20. As is generally known inreusable devices of its type, injection pen 20 includes a medicationfilled cartridge 22 as part of a cartridge assembly, generallydesignated 24, which is connected to a reusable pen base, generallydesignated 26. Pen base 26 preferably includes dose setting andinjecting mechanisms that function to allow a quantity of medicine to beselected and then expelled from cartridge assembly 24 through theinjection needle assembly 27 shown attached thereto. In the shownembodiment, an exposed knob 28 with rotatable button 30 thereon at therearward or proximal end of pen base 26 is a manually operable portionof the dose setting and injecting mechanisms otherwise housed within penbase 26. During the dose setting process, knob 28 is designed to berotatable to set the dose, and when knob 28 is so rotated to increasethe selected dose the knob 28 and button 30 translate out of pen base 26from the axial position shown in FIG. 1, or to the right from theperspective of a FIG. 1 viewer. During the dose injecting process whichoccurs after the dose setting process, when a plunging force is appliedto button 30, which rotates freely relative to knob 28, button 30 andknob 28 are designed to be shifted to the left, and back to the axialposition shown in FIG. 1, to cause the injecting mechanism componentshoused within the pen base to operate to cause the medicine in thecartridge to be injected.

The foregoing is provided as background and is intended to beillustrative and not limiting in any way, as a variety of injectors,having varied manual dose setting and injecting mechanisms, and havingvaried external shapes and sizes, are known in the injection pen art.The inventive drive assembly may be readily adapted for many of suchmechanisms in view of the explanation herein, as the inventive driveassembly described further below in theory may be incorporated into anytype of injecting mechanism that during injection rotates a rotatabledrive element that inputs a rotational force to the drive assembly.Additionally, the inventive drive assembly is applicable toauto-injectors having rotatable drive elements, and further does notrequire the presence of a dose setting mechanism that allows variabilityin the quantity to be delivered.

With additional reference to FIG. 2, in which the needle assembly is notshown attached thereto, cartridge assembly 24 is assembled fromcomponent parts during its production into a unit handled by a user as asingle piece, and disposed of as a unit when the contained medicine isexhausted. Cartridge 22 of cartridge assembly 24 includes an open-endedglass housing 32 that defines an internal volume filled with medicinesuch as human growth hormone or insulin. A slidable plunger 34 engagesinner surface 33 of the cartridge housing in a fluid-tight manner. A rodtip 35 used to distribute advancing forces applied to plunger 34, andwhich is freely movable within the cartridge internal volume locatedproximally of plunger 34, has a base disc 37 integrally formed with acylindrical collar 38 in which fits the distal end 121 of drive screw120 of the inventive drive assembly. If rod tip 35 is eliminated, distalend 121 of drive screw 120 can directly, as opposed to indirectly,engage plunger 34. Alternatively when the pen is to be used withcartridges that lack a rod tip, a foot which has a larger diameter thanthe drive screw and which is designed to rotate relative to the drivescrew may be rotatably mounted on distal end 121 to directly engage thecartridge plunger.

Cartridge 22 is further protected by an outer housing 42, which is shownas being transparent but may be otherwise constructed. At its rearwardend, outer housing 42 includes an externally threaded, stepped-down neckportion 44, and a further stepped-down rear hub 46 in which extends therearward end of rod tip 35. Threaded neck portion 44 allows for athreaded or screw attachment of cartridge assembly 24 to pen base 26.Cartridge assembly 24 includes cap 50 that is secured during production,such as by ultrasonic welding, to outer housing 42 to capture cartridge22 within the outer housing. A pierceable rubber septum 54 is pressed bycap 50 against cartridge housing 32 to seal the open forward end of thehousing. External threads on cap 50 allow mounting of injection needleassembly 27. When assembly 27 is so mounted, the rear end of its needlepierces septum 54, and medicine is expressed from cartridge 22 throughthe needle when plunger 34 is driven to the left in FIG. 1 duringinjecting use of pen 20.

The cartridge assembly which is acted upon by the drive assembly of thepresent invention may be differently configured such as is known in theart. For example, and as further shown in FIG. 7, the cartridge assemblymay be provided as a reusable retainer which is connectable in suitablefashion, such as via threads, to a reusable pen base, and which retainerdefines a chamber into which a disposable cartridge is loaded for use.After the contents of the given cartridge are exhausted by multiple usesof the injection pen, a user disconnects the retainer from the pen base,removes the spent cartridge from the open proximal end of the retainerand disposes of that cartridge, and then inserts a replacementdisposable cartridge into the retainer which is then reconnected to thepen base for use, which cartridge replacement process can be repeated asnecessary. Still further, other cartridge assemblies may be used, suchas a cartridge assembly that includes a disposable cartridge made ofplastic and without an outer protective cover, and which attachesdirectly to the pen base, as well as a cartridge assembly that includesa replaceable cartridge, which mounts or inserts within a chamber of thedevice, and a cover element for the cartridge-receiving device chamber,such as a separate cap piece or an access door that is slidably orpivotally connected to the device.

With additional reference to FIGS. 3-6, the drive assembly includes afloating nut 60 located within the interior hollow of pen base 26defined by the pen base exterior housing. In the embodimentdiagrammatically shown in FIG. 3, the distal end of the pen baseexterior housing includes a cadge interface member 62 fixedly secured,such as by gluing, plastic snap fit or ultrasonic welding, to arearwardly extending housing body portion 64. Interface member 62 isinternally threaded at 66 for connection to the externally threadedstepped-down neck portion 44 for mounting cartridge assembly 24 to penbase 26. External threading 63 of interface member 62 allows mounting ofa not shown main cap of injection pen 20. The inventive drive assemblyalso may be used with other housing configurations.

Floating nut 60 is molded in one piece from plastic and includes agenerally cylindrical, tubular body section 70 which is preferably keyedto the pen base housing to allow the nut to travel in an axial directiontherein while preventing rotational motion of the nut within the housingat any given axial position. A suitable keying includes radiallyprojecting keys 74 located adjacent the rearward end of nut body section70 which fit within axially aligned grooves or keyways 65 formed inhousing body portion 64. In the shown embodiment, three equallyangularly spaced keys 74 are provided, but additional keys, or fewerkeys including only a single key, may be employed. In addition, nut 60may be keyed to the pen base housing by keys furnished on the housingthat fit within keyways formed in the exterior of the nut.

The hollow interior 71 of tubular body section 70 is spanned by diskportion 80 of nut 60. The portion of hollow interior 71 located forwardof disk portion 80 is sized to freely rotatably receive hub 46. Acentral opening 81 defined by disk portion 80 is formed with internalthreads 82 designed to mate with external threading 124 of the driveassembly screw 120. A pair of drive clutch retainers 85 are provided onopposite sides of central opening 81. Each drive clutch retainer 85 is arim or latch portion 87 integrally formed with and projecting radiallyinwardly from body section 70.

Floating nut 60 is forced toward the forward end of pen base 26 by abiasing element acting between nut 60 and, for example, the pen basehousing. One suitable biasing element is a metal, helical compressionspring 90 having a forward end 91 that directly abuts the annular endface 72 of body section 70, and a rearward end 92 that directly abuts aprotruding bulkhead 93 of housing body portion 64. The rear end surface67 of interface member 62 provides an axial stop against which theforward face 75 of each nut key 74 abuts to limit forward axial movementof nut 60 by spring 90. Alternate biasing elements, such as differenttypes of springs and different materials of construction, may besubstituted in other embodiments. The rearward end of the biasingelement alternatively may abut a pen component that is connected to,rather than internally formed with, the housing.

In the embodiment of FIG. 3, drive clutch 100 of the inventive driveassembly is connected to floating nut 60 to be rotatably free andaxially fixed. Drive clutch 100 has a disk shaped body 102 ringedcompletely by a radially outwardly projecting snap ring 104. Whenarranged as shown in FIG. 6 during the device assembly process, movementof drive clutch 100 toward nut 60 results in snap ring 104 ramping upthe resilient clutch retainers 85 with the nut and clutch resilientlydeforming slightly until snap ring 104 axially passes rim portions 87,at which time the pieces snap back to their original form to axiallycapture snap ring 104 between rim portions 87 and a protruding surfaceportion 89 of the proximal face of disk portion 80 which rings centralopening 81. Protruding surface portion 89 has a smaller diameter thanthe distal surface 106 of drive clutch 100 to provide a smaller contactarea to limit frictional resistance to rotation therebetween. Othertypes of latching mechanisms to axially retain the drive clutch withinthe floating nut while permitting relative rotation therebetween,including different numbers of rim portions or rearwardly extending,axially aligned prong portions from which a latch portion projectsradially inward, also may be substituted in alternate embodiments.

Body 102 of drive clutch 100 defines a central opening 110 and has atleast one inwardly extending V-shaped portion or key 112 projectingwithin the opening. Key 112 fits within a corresponding keyway channel122 longitudinally extending along the length of drive or lead screw120, which includes external threading 124 that engages threading 82 offloating nut 60. As shown in FIG. 5, two diametrically arranged keys 112fit within longitudinal keyways 122 located on opposite sides of thedrive screw. The interfitting of keys 112 with keyways 122 causes forcedrotation of drive clutch 100 during injection to rotate drive screw 120,and similarly causes forced rotation of drive screw 120 during reset torotate drive clutch 100.

Drive clutch 100 is adapted to engage a rotatable drive member of theinjecting mechanism for torque transmission. The outer radial region ofproximal surface 113 includes a series of axially projecting, generallytriangular shaped teeth 114 arranged in an annul us, which teeth arestructured and arranged to mate with similarly configured teeth 130provided on drive member 135. Each tooth 114 includes a ramped side 116,and an axially aligned side 118 to which force is directly applied by atooth 130 during driving rotation of drive clutch 100 by drive member135. In alternate embodiments, different torque transmittingconfigurations, including flat plates relying exclusively on frictionfor non-slipping torque transmission, may be substituted for theparticular toothed configuration shown.

The rotatable drive member 135 rotates when injection pen 20 is operatedto cause fluid to be ejected through needle assembly 27. Drive member135 is diagrammatically shown as an annular disc 140 rotatably fixed toa sleeve 142 journaled within the injection pen and through whichextends drive screw 120. Annulus 140 includes the forwardly extendingteeth 130. The inventive drive assembly may be driven by differentlydesigned rotatable drive members within the scope of the invention.

The inventive drive assembly will be further understood in view of thefollowing explanation of aspects of the operation of injection pen 20,starting with the injection pen configured as shown in FIG. 2 whichoccurs when a new cartridge assembly 24 is replacing an exhaustedcartridge assembly that is not shown. The user will first assemblecartridge assembly 24 to pen base 26.

Typically, a user will hold reusable pen base 26 in one hand, andcartridge assembly 24 in the other hand, and first maneuver thecomponents such that distal end 121 of drive screw 120 is insertedwithin hub 46 and rod tip collar 38, and into contact with rod tip basedisc 37. Pen base 26 and cartridge assembly 24 are then manually movedtogether in an axial direction until hub 46 is axially introduced intothe pen base hollow interior and the external threads of stepped-downneck portion 44 initially abut internal threads 66 of cartridgeinterface portion 62. In the course of this movement, rod tip 35 isfirst moved farther into cartridge 22 to close up any spacing that mayhave existed between it and plunger 34, and then drive screw 120 isforced axially and screws through floating nut 60 while drive clutch 100freely spins with drive screw 120 and within floating not 60. The drivescrew 120 is so pushed back or reset, rather than plunger 34 beingforced to slide within cartridge 22, due to the relatively lowfrictional resistance to reset of the drive assembly.

To continue its mounting, cartridge assembly 24 is then rotated relativeto pen base 26 to screw the components together. During an early stageof this rotation, within the housing interior volume, annular shoulder45 contacts end surface 76 of floating nut 60 that is in a forward axialposition due to biasing by spring 90. In alternate embodiments, otherportions of the cartridge assembly, such as the rearward end of hub 46,may be the point of contact with nut 60. In addition, rather than adirect contact or engagement with the nut, the cartridge assembly mayindirectly engage the nut, such as via an interposed member made of alow friction material. Continued screwing in of cartridge assembly 24 bythe user shifts floating nut 60 rearward against a resisting forcegenerated by the compressing of spring 90. In particular, shoulder 45slides along floating nut end surface 76 as the cartridge assemblyrotates and move axially, while nut 60 moves axially withoutsimultaneously rotating. The resisting force generated by spring 90,which increases as the insertion progresses, reduces play betweencartridge assembly 24 and pen base 26 to provide injection pen 20 with amore solid or well-constructed feel to a user, and to limit pen droolingthat can occur during relative movement of the cartridge and the drivescrew.

Cartridge assembly 24 is fully mounted after it has been screwed inuntil end face 43 of barrel 42 abuts the distal face of cartridgeinterface member 62, which arrangement is shown in FIG. 4. Whencartridge assembly 24 is so mounted, nut 60 and the retained clutch 100are in a rearward axial position at which teeth 114 of drive clutch 100are positively engaged with teeth 130 of drive member 135 in a non-slipfashion so clutch 100 can be rotated by rotation of drive member 135.

Subsequently, and with respect to the injection pen 20 shown in FIG. 1,after knob 28 has been dialed out to set a dose, the plunging of button30, which is mechanically interconnected with sleeve 142 of drive member135, rotates drive member 135 to rotate the drive clutch 100 and therebydrive screw 20, which screws out through nut 60 to advance plunger 34 toforce medicine from the needle equipped cartridge assembly 24.

Referring now to FIG. 7, there are diagrammatically shown portions ofanother injection pen equipped with a drive assembly of the presentinvention. In this embodiment, the reusable pen base 226 is similarlyconstructed to that shown in FIG. 3, and further the drive assembly isthe same as that shown in FIG. 3 other than end 121 of drive screw 120being configured to rotatably support an added foot 123. Foot 123 isattached so as to be freely rotatable about the axis of screw 120 duringuse and serves to distribute pressure on plunger 34. The cartridgeassembly in FIG. 7 is in the form of a reusable retainer 230 with adisposable cartridge loaded therein, which cartridge is similar tocartridge 22 but lacks a rod tip 35. Retainer 230 is connectable to thepen base housing such as via threads shown at 232. Cartridge 22 isinsertable into, and removable for replacement from, the retainerthrough the open rearward end of the retainer when the retainer is notconnected to pen base 226. When a retainer 232 with a loaded cartridge22 is mounted to pen base 226, floating nut 60 directly contacts thecartridge housing 32, and the spring biasing of the nut forces cartridge22 toward within the retainer against the interior surface of a notshown forward end of the retainer. Cartridge 22 is thereby preventedfrom moving relative to nut 60.

In still another alternate embodiment which is not shown, the driveclutch need not be held by the floating nut, but instead is simplyshifted into engagement with the drive member by, for example, abuttingcontact with the floating nut. In such a configuration, the springoperably engages the drive clutch to bias it out of engagement with therotatable drive member when no cartridge assembly is properly mounted tothe pen base. For example, the forward end of a spring may abut a washermember which holds forward the drive clutch, such as in contact with thefloating nut.

FIGS. 8-11 show injection clicker assemblies of the present invention,which assemblies may find beneficial application in injection pens, suchas injection pen 20 of FIG. 1. However, and while descriptions of theseassemblies below may make reference to such a pen 20 in general, suchassemblies are not limited to being incorporated into pens similar topen 20. The inventive injection clicker assembly may be readily adaptedfor many alternately configured injectors in view of the explanationherein, as the inventive injection clicker assembly described furtherbelow in theory may be mounted on rotatable drive sleeves of injectingmechanisms which are turned by operation of differently configuredcomponents of those injecting mechanisms. Additionally, the injectionclicker assembly does not require the presence of a dose settingmechanism that allows variability in the quantity to be delivered.

As shown in FIG. 8, one form of the injection clicker assembly of thepresent invention includes a ring-shaped collar or clicker element,generally designated 240. In the description below of the operation ofthe pen portion shown in FIG. 8, such pen portion is described as beinga part of pen 20 shown in FIG. 1 to facilitate explanation, but it willbe appreciated that the pen shown in FIG. 8 includes, for example, adrive assembly which is slightly different than that which is describedabove with respect to pen 20, as well as a cartridge assembly thatcomprises a reusable retainer 238, which is threadably connected to thepen base housing, and a disposable cartridge 22 loaded therein.

Annular collar 240 defines a central bore through which drive sleeve 242extends such that collar 240 is coaxially mounted on drive sleeve 242.At least one rib or key, such as a pair of diametrically opposed keys244, inwardly project within the central bore of collar 240 and slidablyfit within longitudinally extending slots or keyways 246 on oppositesides of drive sleeve 242. The keying of collar 240 with drive sleeve242 results in collar 240 being rotatably fixed but axially movablerelative to drive sleeve 242. In an alternate embodiment, collar 240 canbe keyed to drive sleeve 242 with mating keys and keyways that are onthe drive sleeve and collar respectively.

The proximal face of collar 240 is formed with a ring of axiallyextending teeth 248. Teeth 248 mesh with complementary teeth 250 thatare molded into bulkhead 252. The number of collar teeth 248 and teeth250 to which it engages need not be in a 1 to 1 ratio, as the clickermay have, for example, every other tooth removed. Bulkhead 252 is anadditional component splined to the pen outer housing portion 254, whichouter housing is shown as an assembly of multiple component parts, suchthat bulkhead 252 is rotatably fixed relative to the pen housing duringinjecting use of the pen. Bulkhead 252 is axially fixed in theembodiment of FIG. 8 by being pressed by a spring 256 against a lipportion of the pen outer housing. In alternate embodiments, mating teeth250 may be part of a bulkhead integrally formed with the pen outerhousing.

Teeth 243 and 250 are configured such that when in meshed engagement,only unidirectional rotation of collar 240 relative to bulkhead 252, andthereby to the pen housing, is permitted. During such relative rotation,the collar teeth 248, when traveling across teeth 250, generate audibleclicking noises. The unidirectional rotatability of collar 240 allows itto function as an anti-backup mechanism for the drive sleeve andinjection screw as described further below. In alternate embodiments inwhich no anti-backup feature need be performed by collar 240, teeth 248and 250 may be differently configured so as to not prevent reverserotation and to thereby allow bi-directional collar rotation.

Injection clicker 240 is biased in the proximal axial direction alongdrive sleeve 242 by a biasing element, generally designated 258. In theshown embodiment, the biasing element is a coiled compression springmade of metal which is coaxially mounted on drive sleeve 242, but othertypes of springs or materials of construction alternatively may beemployed. During injecting use of the pen, spring 258 backs up collar240 to provide injection clicks and rotational positioning. Duringmanufacture, springs of various strength can be tested in order toselect a spring that provides a suitable clicking noise withoutmodifying either the bulkhead or the collar design.

The distal end of spring 258 abuts a proximal facing surface of aradially protruding disk portion 260 of drive sleeve 242. The distalfacing surface of disk portion 260 includes a ring of axially extendingteeth 262 that are used to transmit rotational motion of the drivesleeve to a drive assembly that advances the injection screw. In theshown embodiment, which is intended to be illustrative and not limiting,the drive assembly includes a clutch 266 with proximal teeth 264 thatmate with disk portion teeth 262 when the pen is fully assembled asshown in FIG. 8. Clutch 266 is keyed to threaded injection screw 270 viakeys 268 that fit within diametrically disposed keyways 272longitudinally aligned along the screw that extends through drive sleeve242. Clutch 266 is axially retained within, but rotatable relative to, afloating nut, generally designated 275, by way of tangs 277 that snapfit over the clutch during assembly. Floating nut 275 is keyed to thepen housing to be axially movable but rotatably fixed. Floating nut 275is biased distally by spring 256 when cartridge retainer 238 andcartridge 22 is disassembled from the pen base so as to disengage thedrive sleeve teeth 262 from clutch teeth 264 to allow injection screwreset. When floating nut 275 moves distally during pen disassembly, foran injecting mechanism shown in which the drive sleeve is not axiallyfixed, drive sleeve 242 is moved distally by the action of spring 258against disk portion 260, but is prevented from engaging clutch 266 bythe abutment of disk portion 260 against the not shown keys of penhousing portion 255 to which floating nut 275 is keyed.

The injection clicker assembly of FIG. 8 will be further understood inview of the following explanation of its operation within a pen such aspen 20. When pen 20 is in the configuration shown in FIG. 1, which is aready state prior to dose dialing for injection, the teeth of drivesleeve disk portion 260 and clutch 266 are engaged, and the teeth ofcollar 240 and bulkhead 252 are engaged as shown in FIG. 8. During dosedialing or selection, spring 258 maintains collar teeth 248 in meshingengagement with bulkhead teeth 252. Due to the unidirectionalrotatability of collar 240 and its keying to drive sleeve 242, thisteeth meshing rotationally locks drive sleeve 242. With the drive sleeveassembly locked rotationally, the clutch 266, and therefore the drivescrew 270 keyed thereto, cannot rotate, thereby providing an injectionscrew anti-back up feature. During the plunging of button 34 in the doseinjecting process described above, drive sleeve 242, and thereby collar240 keyed thereto, is caused to rotate in the direction permitted by thetooth configuration of collar 240. Rotation of disk portion 260 of drivesleeve 242 rotates clutch 266 and thereby drive screw 270, which screwsthrough an internal threading 279 of nut 275 to advance in the distaldirection to shift the movable plunger of cartridge 22 so as to forcemedication from an outlet of the cartridge. As collar 240 rotates, itoscillates axially, against a proximal directed force applied by spring258, as its teeth ride over bulkhead teeth 250 and create audible clicksthat indicate injecting operation.

Referring now to FIG. 9-11, another form of an injection clickerassembly of the present invention is shown in a different partiallyshown injection pen. This injection clicker assembly is particularlyadapted for an injecting mechanism having a drive sleeve part thatshifts axially during injecting operation. The injection clickerassembly includes a ring-shaped collar or clicker element, generallydesignated 290. Annular collar 290 defines a central bore 292 throughwhich tubular base 335 of the drive sleeve extends. At least one rib orkey, such as a pair of diametrically opposed keys 294, inwardly projectwithin bore 292. Keys 294 fit within longitudinally extending keyways340 on opposite sides of drive sleeve base 335 such that collar 290 isrotatably fixed but axially movable relative to the drive sleeve.

The proximal face of collar 290 is formed with a ring of axiallyextending teeth 296. Teeth 296 mesh with complementary teeth 347 moldedinto a bulkhead 348 integrally formed with the diagrammatically shownpen outer housing.

Each tooth of teeth 296 includes an axially aligned surface 297 and aramped surface 298 extending to the axially aligned surface of thesuccessive tooth, which teeth configuration permits unidirectionalrotation of collar 290 relative to the pen housing that allows thecollar to function as an anti-backup mechanism. During such relativerotation, the collar teeth 297, when traveling across the pen housingteeth 347, generate audible clicking noises.

Injection clicker 290 includes a distal surface 300 which at timesduring pen operation is abutted by a radially aligned, outer region 307of a retainer ring, generally designated 305. Ring 305 includes aforwardly angled, central portion 309 which interference fits during penassembly into a circumferential groove 343 formed in drive sleeve base335. This connection causes retainer ring 305 to follow the axialmovement of drive sleeve base 335 during operation, which axial movementis a function of the particular injecting mechanism of the pen. Retainerring 305 serves to restrict axial motion of collar 290 when the drivesleeve is axially positioned as shown in FIG. 9, such as during dosedialing, by its outer region 307 engaging surface 300, therebypreventing the disengagement of collar teeth 296 from housing teeth 347.

Collar 290 is biased in the proximal axial direction by a coiled metalcompression spring 320 coaxially oriented around drive sleeve body 335.The proximal end 321 of spring 320 fits around a stepped-down diameterneck portion 302 of collar 290. Spring end 321 is pressed over andretained by six ribs 303 spaced at even intervals around the neckportion circumference.

The distal end 322 of spring 320 fits around a stepped-down diameterneck portion 332 of a radially protruding, torque-transmitting member330 of the drive sleeve, generally designated 325. Drive member 330 isthe portion of the drive sleeve which transmits rotational drive sleevemotion to a clutch 350 keyed to drive screw 354. Six ribs 331 evenlyspaced around neck portion 332 are pressed into the distal end 322 ofspring 320 during pen assembly to retain spring 320 to drive member 330.The distal facing surface of drive member 330 includes distally, axiallyextending teeth 333 that mate with teeth on clutch 350 when the pen isassembled for use.

In the embodiment shown in FIGS. 9-11, the drive sleeve is a two partassembly, as radially protruding drive member 330 is configured to allowlimited axial movement relative to tubular base 335 of the drive sleeve,which base is caused to rotate when the injecting mechanism of the penis operated. This ability of relative motion aids in preventing clutchbinding when a cartridge assembly is mounted to the pen base. Inparticular, during cartridge assembly mounting, in the condition thatthe clutch mechanism is meeting tooth to tooth, drive member 330 canback up allowing the cartridge assembly to be fully installed withoutlocking up or damaging the clutch teeth, and any tooth to toothcondition that remains after installation is automatically addressedupon pen priming. This ability of relative motion also allows for theaxial movement of the drive sleeve tubular base during injectingoperation, which movement is a function of the overall injectingmechanism of the pen.

Within a central bore 334 of drive member 330 through which fits tubularbase 335, a pair of diametrically opposed keys 337 project radiallyinwardly. Keys 337 fit within longitudinally extending keyways 340 suchthat member 330 is rotatably fixed but axially movable relative to drivesleeve base 335. A pair of diametrically opposed snaps or ribs 338 alsoproject within bore 334 at locations offset ninety degrees from keys337. During manufacturing assembly of drive member 330 to base 335, ribs338 snap-fit into recesses 341 formed on the periphery of drive sleevebase 335 and in spaced apart relationship from distal end 342. Recesses341 extend in the axial direction greater than the thickness of ribs 338so as to permit the limited axial movement of drive member 330 relativeto base 335. The snap-fit connection prevents the drive sleeve assemblyfrom coming apart axially when a medication cartridge is disassembledfrom the pen base, and further insures that the forward travel of drivemember 330 is limited by drive sleeve base 335 to aid in disengagementof drive member 330 from clutch 350 when a cartridge assembly isremoved.

The teeth 333 of drive member 330 mate with a clutch of a drive assemblyutilized to shift the injection screw distally. The drive assembly shownin FIG. 9 has a clutch 350 internally keyed to a threaded drive screw354 that extends through drive sleeve base 335. Clutch 350 is connectedto a rotatably fixed floating nut 360 which threadedly engages drivescrew 354. Rotation of clutch 350 via the drive sleeve 325 rotates drivescrew 354, which screws through nut 360 to advance in the distaldirection beyond the end of the reusable pen base to shift movableplunger 365 of cartridge 367 so as to force medication from an outlet ofthe cartridge. Floating nut 360 is biased distally by spring 369 whenthe cartridge assembly is removed so as to disengage the drive assemblyfrom drive sleeve teeth 333 to allow injection screw reset. This driveassembly is more fully described above. Other drive assemblies with aclutch that operably engages drive sleeve member 330 when the pen isassembled for use may be used in devices with the inventive injectionclicker assembly.

The injection clicker assembly of FIGS. 9-11 will be further understoodin view of the following explanation of its operation within the pen.When the pen is assembled as shown in FIG. 9, the teeth 333 of drivesleeve member 330 and clutch 350 are engaged and the teeth of injectionclicker 290 and the pen housing are engaged. During dose dialing, drivesleeve base 335 is proximally retained, such as by a not shown spring,causing retainer ring 305 to abut collar surface 300 to keep clickerteeth 296 in meshed engagement with housing teeth 347. Due to the keyingof collar 290 to drive sleeve base 335, this teeth meshing rotationallylocks the drive sleeve base 335, and therefore the drive member 330 dueto its keying to base 335. With the drive sleeve assembly lockedrotationally, the clutch 350, and therefore the injection screw 354keyed thereto, cannot rotate, thereby providing an injection screwanti-back-up feature.

When the injecting mechanism is manually operated during an injectinguse of the dialed up pen, drive sleeve base 335 first moves distally toshift retainer ring 305 distally such that collar 290, subject toovercoming the biasing force of spring 320, is movable distally. Thedrive sleeve body 335 then begins to rotate, and teeth 296 of collar 290shift in and out of engagement with the housing teeth producinginjection clicks. The drive sleeve rotation also causes the drive clutch350 to rotate which screws the injection screw 354 through floating nut360. During this injecting process, if the floating nut floatsproximally slightly, the compressed spring 369 forces it back toward thepen distal end to finish the injection.

In one form shown in block diagram in FIG. 12, a therapeutic doseindicating apparatus of the present invention is housed in a deliverydevice 420 and utilizes an automatic container recognizer 422, adoseable quantity identifier 424, a controller 426, and a display 428.One type of delivery device for which the system is particularly wellsuited is an injection pen, but other types of portable devices, such asa pulmonary device or inhaler, may be similarly equipped.

Automatic container recognizer 422 functions first to recognize acharacteristic of a container insert into delivery device 420, whichcharacteristic in one embodiment relates to a concentration of themedicine within the container, and then to input that information tocontroller 426 as shown at 430. Doseable quantity identifier 424functions first to sense the arrangement to which the dose settingmechanism of delivery device 420 has been manipulated by a user toprepare the device to deliver a finite volume of medicine, and then toinput that information to controller 426 as shown at 432. In response tothe input information, controller 426 calculates the therapeutic dose tobe delivered and instructs display 428 via line 434 to visibly displaythat dosage to a user of delivery device 420.

The delivery device with therapeutic dose indicating capabilities ofFIG. 12 is shown in FIG. 13 as a reusable injection pen, generallydesignated 440. As is conventional in reusable devices of its type,injection pen 440 includes a cartridge assembly, generally designated442, which is connected to a pen base, generally designated 444, whichhouses dose setting and injecting mechanisms that when operated cause aquantity of medicine to be selected and then expelled from cartridgeassembly 442 through injection needle assembly 467.

One form of cartridge assembly 442 is further shown in cross-sectionalview in FIG. 14 and is, but for the identifier described below, the sameas the cartridge assembly 24 of FIG. 2. Thus, cartridge assembly 442includes a cartridge 446 with a glass housing 448 that defines amedication-filled internal volume. The cartridge includes slidableplunger 449, rod tip 452, cap 464 and septum 466. Cartridge 446 isfurther protected by an outer housing or barrel 458 that includes anexternally threaded, stepped-down neck portion 460, and a furtherstepped-down rear hub 462. External threads 468 on cap 464 allowmounting of injection needle assembly 467 that pierces septum 466.

The automatic container or cartridge recognizer 422 of injection pen 440includes an identifier associated with cartridge assembly 442 which isdesigned to work with a sensor that signals controller 426 within penbase 444 based on the identifier sensed. As described in U.S. Pat. Nos.5,954,700 and 6,110,152, the disclosure of which are hereby incorporatedherein by reference in their entirety, the identifier can take manyforms and be used to indicate a variety of facts to the user.

In one form, the identifier is used to represent the concentration ofthe therapeutic contents of the cartridge, assembly, and whichconcentration identifier is disposed on the outer housing hub 462 ofcartridge assembly 442. The concentration identifier possesses specificcharacteristics, such as dimensional and spatial characteristics,recognizable by the sensor of automatic cartridge recognizer 422. Inalternate embodiments, and with corresponding modifications to thesensor of automatic cartridge recognizer 422, the identifier may beplaced on other portions of the cartridge assembly, including but notlimited to cartridge housing 448, and rod tip 452, and further may beused to represent, for example, which one of different possible insulintypes is contained in the cartridge assembly.

The concentration identifier is permanently affixed to the cylindricalexterior surface of hub 462. For cartridge recognition systems thatsense or otherwise read the identifier with elements other than radiallyoutwardly located electrical contacts as described below, for examplewhen the concentration identifier is adapted for use with optical ormagnetic sensors, the identifier need not be exposed on the periphery ofhub 462, and may be differently positioned such as affixed to theinterior surface of hub 462.

As further illustrated in the various embodiments shown and describedwith reference to FIGS. 15-17, the cartridge concentration identifier isshown formed by a single strip of electrically conductive materialfixedly associated with hub 462. The shown strip extends the entire hubcircumference, but may span only a part of the circumference if theassociated sensor contacts of container recognizer 422 described beloware configured to achieve a satisfactory connection despite one or morecircumferential gaps in the strip. The conductive strip nay be in theform of a pad printed conductive ink applied to the hub, however, othermeans of accomplishing the identifier strip may be employed. Forexample, the strip may be a crimped metal band, or a conductiveelectroplating of a material insert molded into the hub, or a conductivepaint, or a pad printed ink, or a metallic self-adhesive label, or anon-conductive adhesive label onto which an appropriateelectrically-conductive pattern has been applied.

Referring now to FIGS. 15-17, hubs 462 a, 462 b and 462 c of threedifferent cartridge assemblies 442 a, 442 b and 442 c each compatiblewith pen base 444, are shown. The type of content identifier shown beingused on hubs 462 a, 462 b and 462 c uses the dimensional aspect of thewidth of the conductive strip, along with the spatial aspect of theplacement of that strip on a hub, to represent the cartridge contents.This type of content identifier has particular applicability toidentifying the concentration of hGH, which has a limited number ofcommon concentrations, and therefore the three cartridge assembliesshown in FIGS. 15-17 each contain hGH in a different concentration. Inother types of content identifiers within the scope of the invention,the dimensional aspect of the identifier strip may be different than thewidth, such as the thickness or texture of the strip.

In FIG. 15, representing a first concentration, a conductive strip 472having a relatively small width, such as about 4.8 mm, encircles hub 462a of cartridge assembly 442 a near the distal end of the hub which isadjacent the threaded neck 460 a of the barrel. In FIG. 16, representinga second concentration, a conductive strip 474 having a relatively smallwidth, such as about 4.8 mm, encircles hub 462 b of a second cartridgeassembly 442 b near the proximal end of the hub. Although the widths ofstrips 472 and 474 are identical to reduce the number of differentlyconstructed parts needed for manufacture of the various cartridgeassemblies, as will be appreciated from the explanation of the deviceoperation that follows, different widths for strips 472 and 474 may beutilized so long as appropriate electrical circuits between the sensorsresult. Finally, in FIG. 17, representing a third concentration, aconductive strip 476 having a relatively large width, such as about 7.1mm, encircles hub 462 c of a third cartridge assembly 442 c and coversnearly the entire hub axial length. The axial region of hub 462 ccovered by strip 476 is the same as would be covered by strips 472 and474 if positioned on hub 462 c at the same locations as such strips arepositioned on hubs 462 a and 462 b, respectively.

Once any of the cartridge assemblies shown in FIGS. 15-17 has beenproperly mounted to injection pen 440, such as by screwing thatcartridge assembly into pen body 444 of FIG. 13, the content identifierof that mounted cartridge assembly provides a conductive path between aseries of sensor contacts within the device which are spaced along theaxial length of the inserted hub. The varying widths and locations ofthe content identifiers of the various cartridge assemblies providedifferent conductive paths between the sensor contacts.

For example, as schematically shown during operation in FIG. 18, thesensor includes electrical contacts 480, 481 and 482. Although thesesensor contacts are shown in FIG. 18 as being in exact axial alignment,each of sensor contacts 480-482 may be angularly spaced from the othersensor contacts, such as within a 60° circumferential span or 120°apart, or such other angular spacing as may be possible within the penbase interior hollow. Furthermore, each sensor contact naturally couldcomprise a plurality of contacts circuited in parallel and positioned atthe same axial hub location. The sensor contacts may be resilient metalfingers extending from a subassembly base pivotally mounted to, forexample, the housing, and circuitry on the base is electricallyconnected to a circuit board of controller 426. The subassembly base isrotationally biased such that hub contact portions of the metal fingersare in a radially retracted position when no cartridge assembly ismounted to pen base 444. When the hub is inserted during connection ofcartridge assembly 442 to pen base 444, through movement of the hub, orof a movable part of the pen base engageable with the hub, such as afloating nut described above, a pivot arm of the subassembly base iscontacted, causing the subassembly base to rotate such that the contactportions of the fingers are moved into communication with the contentidentifier. In an alternate embodiment, rather than pivotable sensorcontacts, the fingers may be resilient or leaf spring type metal fingerswhich are biased radially inward into contact with the hub and which aremounted, for example, to the pen base housing or to a part movablewithin the housing of pen base 444 itself, which fingers slide along thehub as the hub inserts during connection of cartridge assembly 442 topen base 444.

Controller 426 processes the data related to which of the sensorcontacts within injection pen 440 are in communication with theconductive strip of the content identifier and derives information froma look-up table to essentially read what is represented as being withinthe cartridge assembly. For example, sensor contacts 480 and 482 aredirectly circuited with controller 426 by lines 484 and 486, which linesmay be patterns imprinted on a circuit board of controller 426. Sensorcontact 481 is similarly circuited to controller 426 by line 488 whichis grounded at 490. When cartridge assembly 442 b with contentidentifier 474 is loaded as shown in FIG. 18, grounded sensor contact481 is in communication with identifier 474, and the conductivity ofidentifier 474 is used to ground sensor contact 482 and thereby line 486to controller 426. Because sensor contact 480 is not in communicationwith identifier 474, line 484 is not grounded. As a result, controller426 is effectively signaled that line 484 remains open while line 486has been closed, and controller 426 equates this input to a certain hGHconcentration, such as 12 mg, being present within the loaded cartridgeassembly 42 b. (This concentration, as well as other hGH concentrationsreferred to herein, is indicated in mg units, as opposed to mass pervolume units as might otherwise be expected, because that is how theseconcentrations for hGH are normally referenced, such as by physicians totheir patients. Such an indication is a result of the numeric valuerelating to the mass in mg of lyophilized drug before itsreconstitution, which results in the cartridge contents being in liquidform. The concentration in mg/ml can be readily obtained by dividing thereferenced milligram mass by the 2.88 milliliter volume of the cartridgecontents when reconstituted.) In a similar manner, when cartridgeassembly 442 a with content identifier 472 is loaded, grounded sensorcontact 481 is in communication with identifier 472, and identifier 472is used to ground sensor contact 480 and line 484 to controller 426, butsensor contact 482 and line 486 is not grounded, thereby resulting incontroller 426 being signaled that line 486 remains open while line 484has been closed such that controller 426 equates this input to adifferent hGH concentration, such as 6 mg, being present within theloaded cartridge assembly 442 a. Similarly, when cartridge assembly 442c with content identifier 476 is loaded, grounded sensor contact 481 isin communication with identifier 476, and identifier 476 is used toground sensor contacts 480 and 482 and lines 484 and 486 to controller426, thereby resulting in controller 426 being signaled that lines 484and 486 have each been closed such that controller 426 equates thisinput to a different hGH concentration, such as 24 mg, being presentwithin the loaded cartridge assembly 442 c. Finally, when no cartridgeassembly is loaded, or a cartridge assembly without an identifier orwith a defective identifier is loaded, controller 426 is signaled thatlines 484 and 486 each remain open such that no concentrationinformation is available as input.

It will be appreciated that the cartridge recognition system could havemore or less than the three contact points shown in FIG. 18, and coulduse recognizable electrical signals other than ground, such as a smallvoltage, to activate the content identifiers. In addition, in otherforms of the present invention, the cartridge assembly may bedifferently configured such as is known in the art, and such asdescribed above. In an embodiment where a disposable cartridge and areusable retainer is used, the content identifier will be provided onthe disposable cartridge, and pen base 444 will be correspondinglymodified to permit recognition of that cartridge, such as byincorporating part of the recognition system, for example electricalcontacts and wiring, into the retainer, or by configuring the pen basecomponents, such as the contacts, to extend within the chamber of theretainer.

Referring now to FIG. 19, one form of a doseable quantity identifier ofinjection pen 440 is diagrammatically shown. Doseable quantityidentifier 424 includes a rotational matrix, generally designated 500,and a sensor array, generally designated 502, which together arearranged to identify adjustments of the pen mechanism used at least indose selling, as well as preferably in dose injecting after its dosesetting. A variety of mechanisms for setting and injecting a dose areknown in the injection pen art and are therefore not explained inexhaustive detail herein. Moreover, as the inventive doseable quantityidentifier may be readily adapted for such and newly developedmechanisms in view of the explanation herein, the particulars of suchmechanisms explained further herein are intended to be illustrative andnot limiting. Furthermore, in alternate embodiments of the invention inits most general form, doseable quantity identifiers of known designwhich communicate with a controller may be substituted for therotational matrix/sensor array within the therapeutic dose indicatingapparatus of the present invention.

Rotational matrix 500 and sensor array 502 are operably connected tofirst and second components of injection pen 440 which experiencedrelative-rotational motion during operation of the dose settingmechanism by a user to select a volume desired to be injected.

In the embodiment of FIG. 19, the dose setting mechanism includes arotatable dial 506 into which is incorporated rotational matrix 500.Dial 506 is rotationally fixed to an exposed knob 508 that is rotatableby the user to select the dose to be delivered by use of the injectionpen. In the described embodiment, dial 506 when rotated via knob 508translates out of pen base 444, or to the light from the perspective ofa FIG. 13 viewer, during the dialing up of a dose in preparation fordose injecting. However, the inventive matrix need not be on a dial thatso translates, but may be on another rotatable component such as a drivesleeve. In addition, although only one of the first and secondrelatively rotatable pen components is part of the dose settingmechanism in the embodiment of FIG. 19, as the other of these componentsto which sensor array 502 is connected may be the outer housing of penbase 444, the first and second components each may be parts of the dosesetting mechanism in other embodiments.

Shown removed from dial 506 and two-dimensionally in FIG. 20, matrix 500is data arranged in a rectangular array formed of multiple orthogonallyintersecting rows and columns. The number of columns is a function ofthe internal workings of the injection pen, and corresponds to thenumber of rotational positions within one of its revolutions at whichdial 506 can be set to have the injection pen deliver different volumesof medicine. The movement of dial 506 between adjacent rotationalpositions corresponds to a change by one dose volume unit of thequantity to be injected by pen operation, and such change is known as a“click” due to the setting mechanism, as a result of its configuration,producing an audible click-like noise during such movement. The actualquantity of such dose volume unit, for example 0.024 ml, is a functionof the design of the dose setting mechanism as is known in the art.

The data populating matrix 500 is in the form of the presence or absenceof an electrically conductive material at the intersections of the rowsand columns, which electrically conductive data points are showncontiguous or all linked to form a pattern 501 structured and arrangedin conjunction with the sensor contacts of array 502 to conveyinformation to controller 426 of pen 440. The linking allows anelectrical signal delivered to a single data point on pattern 501, suchas a grounding of that point, to travel along the entire pattern asdescribed further below.

Each of the six rows 509, 510, 511, 512, 513 and 514 of matrix 500extends around the entire circumference of dial 506. The twenty-fourmatrix columns 516, 517, 518, 519, 520, 521, 522, 523, 524, 525, 526,527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538 and 539 areequal width, so as each to span 15° of the dial circumference, and arealigned in parallel with the axial length of dial 506. In the shownembodiment, column 516 is unpopulated by any electrically conductivedata points and is formed by a circumferential gap between the ends ofthe conductive pattern portion that otherwise fills row 509 (i.e.columns 517-539) when matrix 500 encircles dial 506. The twenty-fourcolumn matrix design permits twenty-four distinct rotational positionsof dial 506 to be recognized. However, fewer or additional columns thanthe twenty-four shown may be provided within the scope of the invention.In addition, matrix rows different in number than the six shown may alsobe used as long as a suitable pattern recognizable by controller 526results.

The electrically conductive pattern 501 of matrix 500 may be fabricatedby two-shot molding a platable material, such as filled styrene plastic,into an electrically non-conductive or insulating sleeve, which moldedmaterial is then plated with a conductive material, such as successivelayers of copper, nickel and then gold, so as to be electricallyconductive. After plating, the sleeve is fixedly attached to dial 506.To facilitate manufacture, such as to provide a fixturing point neededto position the required pattern, the conductive pattern 501 of matrix500 may include a not shown extension beyond the matrix rows or columns,but which extension is not used by sensor array 502. In alternateembodiments, the matrix pattern may be otherwise manufactured, such as asheet metal matrix insert molded onto a sleeve, or such as in wayssimilar to those described above with reference to the cartridge contentidentifiers, for example via a metallic pattern on a non-conductive;self-adhesive label or flexible, circuit board attached to the dial, orby conductive paint or pad printed conductive ink applied directly tothe dial.

Sensor array 502 operationally engages matrix 500 to sense the matrixdata. For the electrically conductive matrix pattern 501 shown in FIGS.19 and 21, sensor array 502 includes resilient or leaf-spring type metalcontacts 546, 547, 548, 549, 550 and 551 which extend radially inwardfrom a cylindrical base sleeve 544 coaxially arranged on dial 506. Eachof sensor contacts 546-551 abuts matrix 500 within a different row, andin the shown embodiment sensor contacts 546, 547, 548, 549, 550 and 551are respectively aligned with matrix rows 509, 510, 511, 512, 513 and514. Sensor contacts 546 and 549 are installed at a firstcircumferential position of base sleeve 544, sensor contacts 547 and 550are installed at a second circumferential position of base sleeve 544which is spaced 120° from the position of contacts 546 and 549, andsensor contacts 548 and 551 are installed at a third circumferentialposition of base sleeve 544 which is spaced 120° front the positions ofboth contacts 546 and 549, and contacts 547 and 550. This even angularspacing of the sensor contacts around the matrix serves to center thematrix and limit frictional resistance. For this 120° spacing, when dial506 is rotationally oriented relative to sensor array 502 such thatcontacts 546 and 549 each abut matrix 500 within, for example, column516, contacts 547 and 550 each abut matrix 500 within column 524, andcontacts 549 and 551 each abut matrix 500 within column 532.

When sensor contact 546, which serves as the grounding contact asdescribed below, is aligned with column 516, in the shown embodimentthis is the “home” or “zero” position of the dial. When the pen ismanipulated such that no volume of medicine will be delivered if theinjecting mechanism of the pen is operated, the dial will be in thishome position. At the home position, the ground is not electricallyconnected with any of the other contacts 547-551. The matrix pattern canbe adapted to indicate this home position even if, for example, theconductive pattern filled all of row 519 including column 516. For sucha matrix pattern, the pattern would also be configured to not be incontact with any of the other sensor contacts 547-551 when sensorcontact 546 was aligned with column 516.

Matrix pattern 501 shown in FIG. 20 is designed complementary to thiscontact arrangement. Matrix pattern 501 uses a gray code coding schemeto reduce the risk of an error in dial position sensing goingundetected. In the gray code coding scheme, the pattern is configured inview of the sensor positioning such that rotational dial movement, ineither direction and in an amount equal to one column, causes only asingle one of sensor contacts 547-551 to switch its electricalcircuiting relationship with the pattern, which single switching can bemonitored by the controller (i.e. only one sensor contact changes frombeing out of contact with the pattern to being in contact with thepattern, or vice versa, when dial rotation causes each sensor contact inits respective given column to be moved to a column on either side ofthat given column). In the shown embodiment, each of the twenty-fourrotational set positions of dial 506 relative to sensor sleeve 544results in a unique set of information being recognized by operation ofsensor contacts 546-551.

It will be appreciated that column positionings of the sensor contactsdifferent than the three 120° spaced sets described above may be used,for example all of sensor contacts 546-551 being aligned with one of thematrix columns, as long as appropriate modifications are made to theconductive matrix pattern.

To maintain the proper alignment of the sensor contacts with matrixpattern 501, sensor array 502 and rotational matrix 500 are rotatablyfree and axially fixed relative to one another. For the sensorarray/rotational matrix shown in FIG. 19, sensor array 502 may be keyedto, for example, the housing of pen base 444 so as to be free totranslate with, but not rotate with, dial 506 when the dial is rotatedand thereby caused to translate during dose setting. Not shownconnections between dial 506 and sensor array 502 may be used to causesensor array to translate with the dial.

Sensor contacts 546-551 of array 502 are each circuited to controller426 as abstractly represented at line 432 such that sensor input can beused by controller 426 to derive the matrix positioning using a look-uptable in a similar manner as described above with respect to theautomatic container recognizer. For example, during use a ground signalis sent to sensor contact 546, which is in contact with and groundsmatrix pattern 501 at all rotational dial positions except when sensorcontact 546 is aligned in matrix column 516. When electricallyconductive matrix pattern 501 is so grounded, each of sensor contacts547-551 that is in contact with conductive matrix pattern 501 is alsogrounded. The set of grounded/ungrounded signals received by controller426 via line 432 for all of the sensor contacts is used to derive therotational position of the matrix 500, and thereby dial 506, relative tosensor array 502. When sensor contact 546 is aligned with matrix column516, none of the contacts are grounded, which information also isrecognized by controller 426 as indicative of a particular one of thetwenty-four rotational positions of dial 506.

The data of matrix 500 including areas of electrically conductivematerial is due to such data serving to complete electrical circuitswith electrical contacts of the sensor. In alternate embodiments,different matrix data forms may be used with corresponding modificationsto the sensor array. For example, if optical or magnetic sensingelements are to be employed in sensor array 502, the matrix data may bemarkings or magnets, as appropriate.

The matrix/sensor array shown in FIG. 19 is merely one suitable form andmaybe differently arranged within the scope of the present invention.For example, the locations of the sensor array and matrix may bereversed, such that a sensor array 502 circuited to controller 426 ismounted on dial 506 and arranged to engage a rotational matrix disposedon the inner circumference of coaxial sleeve 544.

In addition, and as further described with reference to the embodimentof FIGS. 23-30, both the matrix and sensor array may be disposed oncomponents of the reusable pen base which rotate at different timesduring dose setting and injecting use of injection pen 440. Tofacilitate the signal communication between controller 426 and such arotating sensor array, a slider assembly is disposed therebetween. Asdiagrammatically shown in FIG. 22, an array of sensor contacts 546′-555′are installed on a partially shown first pen component 558 coaxiallymounted on a partially shown second pen component 559. Pen component 558is completely ringed by six electrically conductive, metal bands 560-565that fit within channels in its outer radial periphery. Bands 560-565are in contact with the outward ends of sensor contacts 546′-551′,respectively, that extend through the radial thickness of component 558.Sensor contacts 546′-551′ are similarly structured and arranged to thesensor contacts of the embodiment of FIGS. 19-21, and contact a notshown rotational matrix, similar to matrix 500, that encircles pencomponent 559. Slider assembly 570 includes six resilient electricalcontacts 571-576 having free ends which slide along bands 560-565 as pencomponent 558 rotates, and such sliding contact results in an electricalconnection between sensors 546′-551′ and slider contacts 571-576 at anyrotational position of pen component 558 relative to slider assembly570.

It the internal workings of the injection pen are configured such thatpen components 558 and 559 do not translate or move axially duringoperation, slider assembly 570 may be mounted to a stationary pen basecomponent, such as a microprocessor containing flexible circuit boardfixed to the injection pen housing and which serves as controller 426.Slider contacts 571-576 are connected to circuits on this circuit boardrouted to the controller microprocessor. For this type of sliderassembly mounting, other than limited axial play as may be required forthe working parts of the injection pen, slider assembly 570 is axiallyand rotationally fixed within pen base 444. If pen components 558 and559 translate together during pen operation, slider contacts 571-576 arewired to controller 426 and slider assembly 570 is keyed to, forexample, the pen outer housing and connected to pen component 558 so asto translate with but not rotate with the array of sensor contacts546′-551′.

The injection pen controller 426 that processes signals from the sensorcontacts of the automatic container recognizer 422 and doseable quantityidentifier 424 to determine display information may be constructed andinstalled within pen base 444 in any suitable fashion known in the art.In one embodiment of the invention, controller 426 includes abattery-powered, programmable microcontroller mounted on a main printedflexible circuit board that is generally U-shape and flexible so as toconform to the interior of the pen base housing and to provide a hollowin which extend the internal working parts of pen base 444. The flexiblecircuit board is connected to the housing with locating pins andadhesive. In an alternate embodiment, an application specific integratedcircuit or ASIC may be substituted for the microprocessor.

Injection pen display 428 is operatively coupled to the microcontroller426 and is visible through a transparent housing window of pen base 444.Display 428, such as a liquid crystal display, visibly displays to auser information useful to the operation of the injection pen. Forexample, as best shown in FIG. 13, display 478 is caused bymicrocontroller 426 to display at 580 information about the medicinewithin the held cartridge as recognized by automatic cartridgerecognizer 422, at 582 the amount of therapeutic the injection penstands ready to administer upon the operation of the injecting mechanismof pen 440 as described further below, and at 584 the remaining strengthof the battery that powers the electronic components of injection pen440. The information shown at 580 relates to the concentration of themedicine, as explained further above, but other types of information maybe provided. The units of the dose to be administered is shown in FIG.13 as being imprinted on the underside of the housing window at 586, butmay be part of the display controlled by microcontroller 426.

The design of the therapeutic dose indicating apparatus in injection pen440 will be further understood in view of the following explanation ofits operation. While cartridge assembly 442 is mounted to pen base 444,controller 426 remains in a ready state with all of the display elementsturned off so as to not display any information to a user. In this readystate, controller 426 processes signals received from the sensorcontacts of automatic cartridge recognizer 422 to identify, for example,the concentration of the medicine contained within the cartridgeassembly as represented by the identifier band. In this ready state,controller 426 also processes signals received from the sensor contactsof doseable quantity identifier 424 to identify the position of matrix500 relative to sensor array 502.

Controller 426 advances from the ready state into the operational state,and display 428 is thereby activated, when controller 426 senses furtheruser action on pen 440. For example, such action sensing will typicallybe a recognition that matrix 500 is being moved relative to sensor array502 during manipulation by the user of the dose setting mechanism. Otheraction which may be sensed is operation of a not shown on/off buttonwhich may be located on pen base 444, or as part of knob 508 of theinjecting mechanism.

When advanced to the operational state, controller 426 causes theconcentration identified with automatic cartridge recognizer 422 to bedisplayed at 580. If controller 426 fails to recognize any concentrationinformation, an error message such as “—,” or no message at all, isdisplayed at 580 instead of any numerical concentration value.Recognition failure may result from a cartridge assembly being entirelyabsent from, or not properly mounted to, pen base 444, or from acartridge identifier being damaged or absent from the assembly, or froman internal failure in the automatic cartridge recognizer circuit. Whenconcentration information is not automatically recognized, theconcentration used by controller 426 may be user configurable. Forexample, set button 588 shown in FIG. 13 is circuited with controller426 and is depressable to select, and have displayed at 580, any of thestandard concentration values, such as 6, 12 and 24 mgs in the case ofhGH, preprogrammed into controller 426.

While controller 426 is in the operational state, as knob 508 is rotatedby a user to set the dose to be delivered, controller 426 continuallyreceives input in real time from the sensor contacts of doseablequantity identifier 424 to identify the position of matrix 500 relativeto sensor array 502. Controller 426 processes the input to determine towhich position the dial 506, and therefore matrix 500 in the shownembodiment, has been rotated from the “zero” dial position at which novolume of medicine will be delivered if the injecting mechanism of thepen is operated. For example, if the “zero” dial rotational position iswhen sensor 546 engages column 516, controller 426 recognizes whensensor 546 is in engagement with each of columns 517-539 to determinewhich percentage of a dial revolution has been made. Typically,automatically during, or manually after, injection of the set dose thedial is returned to its original “zero” position for subsequent use.However, controller 426 may be designed to determine dose setting basedon any starting point of the dial.

Controller 426 senses the rotational position of the dose setting dialvia the matrix/sensor array interface whether the dial is being rotated,or dialed up, so as to increase the set dose, or being dialed down todecrease the set dose. In addition, controller 426 is programmed toaccount for one or more complete dial revolutions during dose setting.During dose setting, by recognizing the matrix position relative to thesensor array at the orientation from which the dial is being rotated,controller 426 recognizes in which direction the dial is being rotatedduring movement to the “zero” dial rotational position. Specifically, ifthe “zero” dial rotational position is when sensor 546 engages column516, controller 426 recognizes that the set dose is being increased ifsensor 546 reaches column 516 immediately after being in column 539, andthat the set dose is being decreased if sensor 546 reaches column 516immediately after being in column 517.

For example, with the dial initially arranged in the “zero” dialrotational position, during dialing up when that “zero” dial rotationalposition is reached for the first time and the dialing up continues, andthen the “zero” dial rotational position is reached for the second timeand the dialing up continues, when controller 426 senses via thematrix/sensor array that, for example, dial rotation is halted by a userwhen the dial reaches the sixth rotational position from the “zero”position, controller 426 recognizes that a fifty-four unit volume dosehas been set for injection (i.e. two complete revolutions each oftwenty-four positions or unit volumes in the shown embodiment plus thesix additional positions). If a dose is initially set at too large anamount by a user who then reduces that dose setting before injecting,dialing down through the “zero” rotational position attained at one ormore complete dial revolutions will be accounted for by controller 426.

The dose volume that controller 426 identifies with doseable quantityidentifier 424 is used to display the actual therapeutic amount to beinjected. Specifically, controller 426 essentially multiplies theconcentration displayed at 580 by the volume set by rotation of dial 506and causes the injectable amount of therapeutic to be displayed at 582.The multiplication step described above is normally performed bycontroller 426 referencing a look-up table populated with data based ontherapeutic concentration and the number of dial “clicks” selected. Thedisplay at 582 displays the injectable amount at all times throughoutthe dose setting process. For example, when each “click” corresponds toa unit dose volume of 0.024 milliliters, when the cartridgeconcentration is 6 mg as explained above, each dialing up of dial 506 inan amount of 15 degrees, or one click, causes display 582 to beincreased by 0.05 for the shown milligram labeling, and similarly whenthe cartridge concentration is 24 mg, each one click dialing up of dial506 causes display 582 to be increased by 0.20 for the shown milligramlabeling. Thus, at all times the amount of therapeutic displayed at 582is the medically significant amount actually injectable by operation ofinjection pen 440. No calculations based on the concentration of hGHloaded in the cartridge assembly 442 need be made by the user to figureout how much hGH is being injected.

In addition, the display amount at 582 also works throughout injection(i.e., displays the quantity still to be injected) if the pen componentson which the matrix and sensor array are disposed are designed toappropriately rotate relative to each other during injection.

After injection pen 440 is used to inject the set dose, such as byaxially pressing on knob 508 and moving dial 506 back into pen base 444,controller 426 automatically returns to an off state, and the displayelements of display 429 all turn off, following a certain time period ofinactivity. In the event after dose setting no injection is immediatelymade, the display remains on until the injection is made, after whichthe pen turns off after the above-described inactivity.

As further described below, the doseable quantity indicator may be usedin delivery devices that lack the automatic cartridge recognition systemdescribed herein, such as in devices in which different medicines eachhaving only a single concentration are being delivered. In such devices,the display at 582 can be a numerical value or another piece ofinformation representative of the actual doseable volume.

Referring now to FIG. 23, there is shown an exemplary embodiment of amedication injector apparatus with an assembly for selectively rotatinga drive sleeve of the present invention. The apparatus, generallydesignated 620, is shown in the form of a reusable injection pen,although other forms of portable injectors are within the scope of theinvention.

Injection pen 620 includes a reusable pen base, generally designated622, to which is attached a cartridge assembly generally designated 624and further referenced in FIG. 25. In FIG. 23, the cartridge assembly isshown substantially encased within a removable cap assembly 626. Asfurther shown in FIG. 27, cap assembly 626 comprises a metal tip clip627 swaged to metal cap shell 629, and a plastic tubular cap insert 633that is secured within shell 629 and includes modules for attachment tothe cartridge holder. Insert 633 is not shown in FIG. 24 to facilitateillustration. Pen base 622 houses a dose setting and injecting assemblythat when operated causes a quantity of medicine to be selected and thenexpelled from cartridge assembly 624 through pen needle assembly 628further referenced in FIG. 24.

With additional reference to FIGS. 24-27, cartridge assembly 624 is of ageneral type known in the art and includes a reusable cartridge holderor retainer 630. The proximal end 631 of holder 630 is connectable in asuitable fashion, such as via an internal threading, to the distal endof pen base 622. Holder 630 defines a chamber into which a disposablecartridge 632 is loaded for use.

Cartridge 632 is of a standard design generally described above andincludes a medication-filled glass housing 634, piston 638, septum 644and cap 646. A foot 640 that is rotatably secured via a one timesnap-fit on the distal end of a drive screw 780 extendable from pen base622 distributes moving force on piston 638. Openings or windows 642 onopposite sides of cartridge holder 630 allow visual observation of thequantity of medicine remaining within the held cartridge. Externalthreads 650 on the distal end of cartridge holder 630 allow mounting ofhub portion 652 of pen needle assembly 628. When assembly 628 is mountedas shown in FIG. 24, the proximal end 654 of needle cannula 656 held inhub portion 652 pierces septum 644, and medicine is expelled fromcartridge 632 through needle cannula 656 during injecting use of pen620. Although the needle assembly is shown as having a single injectionneedle, needle assemblies which may be used with pen 620 may be ofvarious pen types known in the art, including, but not limited to,assembles with one or more shortened injection needles, includingmicroneedle arrays.

In the shown embodiment, pen needle assembly 628 further includes aneedle cover 658 which has an interference fit to hub portion 652. Capassembly 626 hits over the distal end of cartridge assembly 624 when pen620 is not being used, and is removably snap fit to cartridge holder 630using mating detents and indents. A camming feature on cartridge holder630 serves to rotationally align cap assembly 626 properly on cartridgeholder 630 when being connected together, and further pushes capassembly 626 axially away from the cartridge holder 630 to disengage anysnap fit therebetween when the cap assembly is rotated relative to thecartridge holder during its removal therefrom. A decorative trim ring662 is fixedly connected, such as via adhesives, around proximal end 631of cartridge holder 630 for aesthetic purposes.

In pen 620, after the contents of a given cartridge 632 are exhausted byuse of the injection device, a user disconnects holder 630 from the penbase 622, removes and disposes of the spent cartridge 632, and theninserts a replacement, disposable cartridge into the reusable holderwhich is then reconnected to pen base 622 for use. Windows 642 help ingripping the cartridge during the removal of the cartridge from holder630.

In an alternate embodiment not shown, and rather than the separablecartridge and holder shown, the cartridge assembly may be differentlyconfigured as is known in the art, and such as described above. Forexample, the cartridge assembly 624 may be assembled from componentparts during production into a disposable unit handled by a user as asingle piece.

Cartridge holder 630 is removably mounted to pen base 622, by screwingits internally threaded proximal end onto the external threading 664 ofa tubular front housing 666. Front housing 666 is snap fit via angularlyspaced detents 667 to a distal end of a housing main body, generallydesignated 670. Angularly spaced keys 668 of front housing 666 fitwithin keyways 671 of housing main body 670 to prevent relative rotationtherebetween.

The housing main body 670 is molded in one piece, but a multiple pieceassembly may be employed. Housing end cap 676 is snap fit via itsprotruding collar 677 to the proximal end of main body 670 to be axiallyfixed together.

Proximally extending beyond and axially shiftable through the centralopening of end cap 676 is a cylindrical sleeve-shaped dial 680. A set ofthree angularly spaced notches or keyways 681 located along the proximaledge of dial 680, and a set of three snap slot recesses 682 in the dial,respectively accommodate keys 692 and latching ribs 693 of a base 690 ofa dial assembly to provide a rigid, permanent assembly of dial knob base690 with dial 680 via a one-time snap fit. The dose knob assemblyincludes a cover 695 that is fixed to base 690 with adhesive, and withkeys 696 of cover 695 fitting in notches 694 of base 690. In oneembodiment, dose knob base 690 is plastic and cover 695 is a die-castcomponent. Gripping features 697 formed in the exterior periphery ofcover 695 enhance gripping of the dial knob assembly during its rotatingor dialing to set the dose. Within its interior, dial knob cover 695includes a centering protrusion, or alternately a ring-shaped seat,which centers the distal end of priming spring 699.

Adjacent its distal end, dial 680 includes a pair of radially protrudingkeys 683 which insert within longitudinally extending keyways (notshown) formed in the interior surface of barrel 700. This keyingprovides consistent rotational movement between dial 680 and barrel 700while permitting dial 630 to move axially relative to barrel 700. Adouble start helical threading 685 radially inwardly protruding from thecylindrical interior surface of dial 690 mates or screws into helicalgrooves 712 formed in the exterior surface of a drive sleeve 710 of adrive sleeve assembly, generally designated 708. By making one of thedouble start threads 685 and its corresponding groove 712 thinner thanthe other thread and groove, a one way assembly of the dial to the drivesleeve is achieved. Different thread configurations, including a singlethread and groove connection, may be used in alternate embodiments. Anarrowhead 686 formed on dial 680 shows the direction dial 680 isinserted onto drive sleeve 710 to facilitate assembly. Zero stop 713 isthe distal end of grooves 712 which is abutted by dial threading 685 toprevent the dial 680 from being dialed below a zero setting of the pen.A maximum dose stop, formed of a collar 720 with a pair of axiallyextending latching prongs 721 that snap fit into recesses 714 in drivesleeve 710, fits around the proximal end of drive sleeve 710 to engagedial threading 685 at the proximal end of grooves 712 to prevent thedial 680 from being dialed above a maximum setting.

Barrel 700 is formed with an annular rib 702 at its proximal end thatextends continuously around the outer circumference of the barrel. Thedistal face of barrel rib 702 includes a series of axially extendingunidirectional teeth 703 for engagement with an annular dial clicker725. The proximal face of dial clicker 725 includes a ring of axiallyextending, unidirectional teeth 726 that mate, with barrel teeth 703.The distal face of dial clicker 725 includes a ring of axiallyextending, unidirectional teeth 728 that mate with axially extending,unidirectional teeth 732 on the proximal face of an annular dial clutch730.

A set of four keys 733 protrude radially outwardly from the externalperiphery of clutch 730 and slidably fit within axially extendingkeyways 673 in housing main body 670 to prevent rotation of clutch 730relative to the housing. A helical compression spring 735 having one endabutting a bulkhead 672 formed in housing main body 670 and the otherend seated on the distal face of dial clutch 730 biases clutch 730 intoclicker 725 into barrel rib 702 to provide audible clicks during dosedialing and to provide rotational positioning during dialing. Inparticular, when dial 680 is dialed up so as to axially move proximally,clicker teeth 728 slide past clutch teeth 732 as the meshing of clickerteeth 726 with the teeth 703 of the rotating barrel 700 causes rotationof clicker 725. When dial 680 is dialed down, the barrel teeth 703 slidepast clicker teeth 726 as clicker 725 is rotatably fixed by the meshingof clicker teeth 728 with teeth 732 of the rotatably fixed clutch 730.As is known in the art, this sliding motion of the teeth produces thedial clicks.

Barrel spring 735 biases barrel 700 proximally such that except duringinjecting operation of pen 620 as described below, the axially extendingexternal splines 704 at the barrel distal end do not mesh withcomplementarily internal splints of bulkhead 718 formed in housing mainbody 670. The splines of bulkhead 718 are twenty-four in number andequally angularly spaced circumferentially around the drive sleeve. Theproximal retraction of barrel 700 is halted when the proximal face ofbarrel lip 705 abuts drive sleeve flange 716 and the drive sleeve hasbeen retracted proximally until ring 760 has pressed clicker 754 intofull engagement with splines of the housing bulkhead 718. Splines 704are integrally formed on inward lip 705 of the barrel in four arcuatesegments, the spacing between segments providing clearance for lugs 655.The proximal face of lip 705 also serves as a contact face for injectionforce that is placed on drive sleeve 710, as well as a bearing surfacefor the relative rotational movement of drive sleeve 710 and barrel 700.

When barrel 700 is shifted distally so as to compress barrel spring 735during injecting, barrel splines 704 mesh with internal splines ofbulkhead 718 to prevent rotation of barrel 700 relative to housing 670.In an alternate embodiment, the prevention of rotation of barrel 700relative to housing 670 may be accomplished with interfacing,unidirectional teeth.

The distal region of drive sleeve 710 is generally cylindrical, althoughshown with slight facets for improving manufacturability, and includescircumferential groove 748, diametrically opposed recesses 750 anddiametrically opposed longitudinal slots 746. Injection clicker 754 isrotatably fixed with drive sleeve 710 by four 90° spaced apart lugs 655integrally formed with the drive sleeve which fit into fourcorresponding recesses 647 in the proximal face of clicker 754. Clicker754 is biased in the proximal direction by clutch spring 758. Retainerring 760 fits in groove 748 and prevents disassembly of the clicker fromthe drive sleeve. When drive sleeve 710 is biased proximally byoperation of barrel spring 735, lugs 655 engage the splines of bulkhead718 and prevent rotation of drive sleeve 710. When the biasing of barrelspring 735 is overcome and the drive sleeve is shifted distally duringinjecting, lugs 655 are shifted away from bulkhead 718 to allow lugs 655to disengage from splines of bulkhead 718, thereby allowing the drivesleeve 710 to rotate. Clicker 654 is allowed to move axially withrespect to the drive sleeve allowing clicker teeth 656 to slide over theramped end faces of the splines of bulkhead 718 when drive sleeve 710 isrotated to create an audible clicking indication of operation and toprovide a rotational positioning during injection. The distal end ofclutch spring 758 abuts the proximal face of an injection clutch 762that is rotatably fixed with drive sleeve 700 by keys 764 that sidewithin slots 746. Clutch 762 is further snap fit within recesses 750 soas to have a limited axial play on drive sleeve 710 to accommodate theaxial motion of the drive sleeve during injecting, and axial travel ofthe floating nut 776 during installation of the cartridge assembly 624.The distal face of clutch 762 includes a ring of torque transmittingteeth 766.

Clutch teeth 766 selectively mate with teeth 772 of a drive clutch 770axially retained within injection not 776. Internal keys 774 of clutch770 slide within two longitudinal keyways or slots in threaded drivescrew 780 and cause the drive screw to be rotated with the clutch. Thedrive screw keyways or slots are formed by corner to right triangularshaped cuts in the screw along its length, which cuts are generally onopposite sides of the screw. The lead edge of the first corner cut isradially aligned in the screw, as well as diametrically aligned with thelead edge of the second corner cut, resulting in the non-aligned ortrail edges of the first and second corner cuts being parallel. Drivescrew 780, which extends within an axial bore through drive sleeve 710,threadedly engages an internally threaded bore within injection nut 776.Nut 776 is rotatably fixed but axially movable within housing 670 viaangularly spaced keys 777 that slide within axially aligned recesses 674in housing main body 770. When drive screw 780 is caused to be rotatedby the forced rotation of drive clutch 770, the drive screw advances inthe distal direction as it screws through nut 776. Priming spring 699press fits onto the proximal end of drive screw 780. During cartridgereplacement, when screw 780 is driven back when being reset duringmounting of a replacement cartridge-filled cartridge assembly 624 to penbase 622, spring 699 is compressed upon contacting the dial knob cover695 to bias the drive screw forward toward cartridge piston 638.Injection nut 776 is biased in the distal direction by an injectionspring 784 that acts between a housing bulkhead and the proximal face ofnut 776, which biasing is overcome by engagement with the distal end ofcartridge 632 during mounting of cartridge assembly 624.

In the embodiment shown, electronics are used in determining anddisplaying the dose that is set and remaining to be injected duringsubsequent use of pen 620. Therefore, in the shown embodiment, dial 680need not be furnished with any numbers or other markings that provide auser with a visual indication as to what quantity of medicine the penhas been manipulated to inject upon use, and the dial thus serves as anextension of the grippable knob. The electronics include an electricallyconductive matrix pattern 800 around a plastic sleeve 802 that is fixed,through a method such as adhesive bonding, a snap fit or press fit, todrive sleeve 710. A not shown, axially extending key of sleeve 802 fitswithin an opening in annular flange 716 of drive sleeve 710 to preventrelative rotation, and allows for a proper orientation of the matrix 800relative to drive sleeve 710. Flange 736 also provides a bearing surfacefor the relative motion between drive sleeve 710 and barrel 700, takesthe distal axial load of injection, as well as takes the proximal axialload of retraction by spring 735. The matrix-including sleeve 802together with drive sleeve 710 form the drive sleeve assembly 708 thatrotates and translates as a single unit during operation.

Matrix sleeve 802 is electrically contacted by contact ends of a pair ofinsert molded leaf spring contact assemblies, generally designated 805and 806, further shown in FIG. 29. Contact assembly 805 includes aplastic base 807 that inserts within the cross portion of a T-shapedopening 808 in barrel 700. A wedge shaped periphery of base 807 preventsover insertion. Four metal leaf springs 810, 811, 812 and 813 arecaptured in base 807. The matrix contact ends 810 a, 811 a, 812 a and813 a of leaf springs 810-813 extend through the base of opening 808 andbrush against the matrix sleeve to make electrical contact with theconductive pattern 800. Wire contact ends 810 b, 811 b, 812 b and 813 bof leaf springs 810-813 extend external to barrel 700 and fit within thefour most proximal circumferential grooves 706 of a set of six suchgrooves in the exterior of barrel 700 which accommodate contact rings.

Contact assembly 806 is similarly constructed to contact assembly 805with a plastic base 814 holding three metal leaf springs 816, 817 and818 including matrix contact ends 816 a, 817 a and 818 a, and wirecontact ends 816 b, 817 b and 818 b. Plastic base 834 inserts within anot shown barrel opening that is longitudinally and angularly offsetfrom barrel opening 808. Wire contact ends 816 b, 817 b and 818 b extendexternal to barrel 700 and fit within the three, most distalcircumferential grooves 706 of the set of six such grooves. By placingcontacts 813 and 816 at the same longitudinal position and in the samegroove 706, a redundant contact for grounding the matrix pattern isprovided. In the shown embodiment, matrix contact ends 816 a, 817 a and818 a are angularly offset 90 degrees from matrix contact ends 810 a,811 a, 812 a and 813 a, but other spacings may be employed.

With reference again to FIG. 27, encircling barrel 700 are six contactrings made of metal wraps or coiled springs 820-825. Rings 820-825 seatwithin the six axially spaced, circumferential grooves 706 in theexterior of barrel 700, as well as grooves 809 formed in base 807 andgrooves 815 of base 814, and are in electrical contact with wire contactends 810 b, 811 b, 812 b, 813 b and 816 b, 817 b and 818 b,respectively. Rings 820-825 allow contacts of a rotationally stationaryslider assembly 838 to remain in contact with the rings regardless ofthe relative rotational positions of the rings.

Matrix 800 is designed and constructed conceptually similar to matrix500, but is adapted to work with the angular positonings of matrixcontact ends 810 a, 811 a, 812 a, 813 a, 816 a, 817 a and 818 a suchthat twenty-four different angular orientations of barrel 700 relativeto drive assembly 710 can be recognized. One suitable matrix 800 isshown two-dimensionally in FIG. 30. The rounded protrusions shown on thematrix in FIG. 30 are not part of the effective pattern, but rather areused to help hold the pattern in the part into which it is insertmolded. Still further, the pattern of matrix 800 is designed so thatsingle-point errors in contacts related to matrix data associated withthe contact ends 810 a, 811 a, 812 a, 817 a and 818 a, and not theground contact ends 813 a and 816 a, that are different than the changeexpected by moving from one matrix position to an adjacent matrixposition in either direction are readily detected by controller 867 forthe purpose of detecting errors in the pen operation at all times thepen is on. Specifically, the matrix 800 is designed such that duringrelative rotational motion of the pen components which moves the matrixone position from its current position (e.g., a movement of 15° for thetwenty-four column matrix shown), the change of one of the signalsassociated with matrix contacts ends other than contacts 813 a and 816 aresults in only one of the following: (a) a shift to the codecorresponding to an adjacent position, (b) a shift to a codecorresponding to none of the twenty-four positions, or (c) a shift to acode corresponding to a position outside of a given range, such as arange from two to six positions inclusively away from the currentposition. Other ranges, from two to three or four or five positions, ortwo to eight or more positions, may alternative be employed. In otherwords, for any of the twenty-four rotational positions, the code of thematrix data within the range of two to six positions away from a givenposition in either direction differs by at least two data points fromthe given position. Thus, during pen use, whether during manual dialingup a dose, or manual dialing down a dose, or during medicine injecting,if the controller receives information suggesting a movement of greaterthan six rotational positions from the previously recognized position,which such movement is considered by the pen to be too large a movementand therefore an error, unless within a short period of time set by themanufacturer, such as the time between display updates, during whichtime the controller continues to check the matrix data, the receivedinformation is back within the accepted range of positions from thepreviously recognized position, the controller causes an error messageto be displayed. If the received information does return to the acceptedrange within the set period, the pen controller recognizes the erroneousreading as being an aberration and ignores it as such, and does notdisplay an error message or require a resetting of the pen.

It will be recognized that one skilled in the art, in view of theteachings herein, can provide other ways for controller 867 to determinethe validity of a sensed position code, based upon a previouslyrecognized position code. For example, it is not necessary for thematrix 800 to provide unique patterns for all twenty-four positions of arevolution, but only for those positions within a valid range, such asone to six positions, on either side of any given position. Thecontroller would compare a sensed position code to the position codeswithin the range adjacent the previous code to determine around which ofthe non-unique position codes was being sensed. The foregoing approachwould allow the twenty-four positions to be captured through a five-rowmatrix, which is a four-bit signal, instead of the shown six-row matrix800, which is a five-bit signal. The reduction to a five-row matrix isnot required, but could be used to reduce the number of parts ordecrease device length. If a five-bit signal were still to be used, suchmay improve the overall reliability of the device without increasingdevice length because redundancy may be added.

Still further, a matrix 800 could be created where matrix dataassociated with two matrix contact ends other than contact ends 813 aand 816 a change when shifting one column of the matrix 800, instead ofonly one data point as described directly above. Such an approach wouldallow controller 867 to reject all single-point error of such sensorcontacts instead of only those that would result in a change of morethan one data point, thereby improving the reliability of the device.For such a two-bit shift, if twenty-four unique rotational positions aredesired, a seven-row matrix pattern, as opposed to the six-row patternshown, will be required.

Each of contact rings 820-825 is directly engaged by one of six slidingcontacts 840-845 of a slider assembly, generally designated 838, shownfurther in FIG. 28. Sliding contacts 840-845 are made of metal in a leafspring form and are mounted on a plastic chassis 847 between a pair ofkeys 849 that radially project from the chassis. Keys 849 insert withina pair of circumferential grooves or keyways 707 in barrel 700 thatflank on either axial side the set of six grooves 706. The fitting ofkeys 849 within grooves 707 causes slider assembly 838 to move axiallywith barrel 700, but allows barrel 700 to be rotated relative to sliderassembly 838, all the while with sliding contacts 840-845 in electricalcommunication with contact rings 820-825.

Slider assembly 838 is fixedly connected to a flexible circuit board 865such that the contacts can transmit to the microcontroller via thecircuit board 865 the sensed matrix patterns. Slider assembly 838 ispositioned on the board during manufacture via a pair of nubs thatproject from the back of chassis 847 and fit within notches 851 in theboard. Slider assembly chassis 847 fits within opening 678 of housingmain body 670, which opening serves as a keyway in which slider assembly838 is axially movable but rotatably fixed relative to the housing.

To accomplish sensing of relative motion of barrel 700 and drive sleeveassembly 708, the matrix 800 on sleeve 802 provides a selectiveconductive path between the six contact rings 820-825. Contact ring 823is always grounded, and that grounded ring, via its associated matrixcontact ends 813 a and 816 a, is always in contact with and therebygrounds the conductive matrix 800, except at the home rotationalposition when none of the other rings 820, 821, 822, 824 and 825 viatheir associated matrix contact ends is in contact with the matrixpattern 800. The matrix pattern 800 selectively shorts the currentacross the appropriate rings to form a code that is then picked up byslider contacts 840-845 and sent to the microcontroller for recognition.

Although described above as the matrix being grounded, in otherembodiments, the matrix could be activated not by a ground signal, butrather by any voltage that is distinctly recognizable by the controller.For example, for a controller where the only options are logic high andground, rather than the ground signal described above as being theactivating signal, a logic high signal of approximately three volts maybe used to activate the matrix.

Slider assembly 838 also includes an injection switch, generallydesignated 853. Switch 853 has a resilient contact 855 made of metal ina leaf spring form and with a ramped region 857. When barrel 700, andthereby slider assembly 838, are moved axially a short distance during afirst phase of injecting operation, ramped region 857 is pressedradially outward by contact with housing surface 679 such that resilientcontact 855 completes a circuit with fixed contact 861 of the injectionswitch. Resilient contact 855 includes a contact end 859, and fixedcontact 861 includes a contact end 863, that are each electricallyconnected to circuit board 865 to convey electrical signals to themicrocontroller. During this slider assembly axial movement, the portionof flexible circuit board 865 to which the slider assembly is mountedalso moves axially relative to the remainder of the board. The closingof injection switch 853 is recognized by microcontroller 867 as thestart of the injecting operation of the pen, rather than the pen beingdialed down or up in preparation for injecting.

Flexible circuit board 865 is a two-layer flexible circuit board thatwraps around the housing main body 670 and is connected to main body 670with locating pins and adhesive. Flexible circuit board 865 serves asthe base to which are mounted microcontroller 867, which is programmedto control the electronic operations of pen 620, batteries 869 forpowering the electronics, and an LCD display 871.

The electronics of pen 620 are capable of sensing the relativerotational motion of the drive sleeve assembly 708 within the barrel700, which barrel and drive sleeve assembly are maintained in aconsistent axial position with respect to each other. During dosesetting, barrel 700 rotates while drive sleeve assembly 708 isrotationally fixed within the housing, and during dose injecting thebarrel is rotationally fixed and the drive sleeve assembly rotateswithin the housing.

A clear plastic lens 873 is adhered to housing main body 670, andprotectively covers display 871 and provides magnification of thedisplay readout. Push button 875 used in controlling the pen electronicsis pivotally mounted to lens 873 and interfaces with a switch actuator874 that activates a snap dome switch that is electrically connected tocircuit board 865. The microcontroller 867 is programmed to turn on thedisplay for operation when button 875 is manually depressed. In oneembodiment, button 875 can be used to change data stored in memory, or asetting of a clock associated with the microprocessor. For example, datastored in memory associated with the microprocessor, such as, the date,is adjustable by first pressing and holding button 875 for a set period,such as three seconds, to transition the pen into an adjust mode, andthen by axially pressing on the dial knob assembly to move sliderassembly 838 and activate injection switch 853 to increment the databeing changed. A bezel 877 adhered to housing main body 670 serves as adecorative trim piece and along with lens 873 and push button 875 isexposed through a window 879 of an outer skin 880 formed from metal andwhich is adhered to housing main body 670.

A seal 882 made of foam is captured between the underside of lens 873and an upper surface of the flexible circuit board 865. Seal 882 resistsany fluid that may be present on the pen exterior along theinterconnection of the push button 875 and lens 873 from reaching theinternal electronics of pen 620. A frame filler 885, which is providedto facilitate pen assembly and fits within notches in housing main body670, serves as an additional base on which display 871 is adhered, andis an additional bonding surface for skin 880.

A cover portion 887 is adhered to the underside of housing main body670, and has internal relief to allow room for the electronics. A metalouter skin 880 is adhesively mounted to both housing main body 670 andcover portion 887 to provide an attractive appearance to pen 620.

The structure of injection pen 620 will be further understood in view ofthe following explanation of its operation. When the user needs toinject herself with a dose of the medication, pen 620 first is turned onby depressing button 875, which causes display 871 to display thecurrent date and time according to the pen's internal clock, and a “0”as to the amount of medicine the pen is prepared to deliver. Pen 620also may be turned on by beginning to rotate the dial knob assembly, oralternatively by pressing the dial knob assembly to trigger theinjection switch. If after the pen is turned on via button 875 or bypressing the dial knob assembly, the dial knob assembly is axiallypushed distally such that injection switch 853 is activated, the date,time and amount of the last injection is caused to be, displayed. If thememory of pen 620 is adapted for multiple dose memory, each additionaldistal plunging of the dial knob assembly will cause the then previousinjection date time and amount to be displayed, so that the user cancycle through the stored previous doses, which may be ten or more doses.To exit the dose memory mode, the user can wait for a set period oftime, such as eight seconds, without dialing the dose knob or pressingany buttons or by dialing the dose knob from the “0” position, or bypressing and releasing the dose knob a sufficient number of times tocycle through the entire multiple dose memory.

Pen 620 is then manipulated such that the user selects the dose to beadministered. The following explanation will assume pen 620 has alreadybeen primed as is suggested, which priming step merely involvesoperating the part in the manner described below to discharge a smalldose to expel any air from the cartridge. In a pen having multiple dosememory, an indication that such dose was a priming dose can be tagged inmemory, such as by pressing and releasing mode button 875 immediatelyfollowing the prime delivery so long as the microprocessor 867 sensesthe injection switch 853 is no longer activated, such as prior to thecompletion of a five-second post injection timer. When a user reviewsthe doses in memory, a priming dose may be indicated by that dosealternating over time with a “P” in the display. The prime tagalternatively may involve a press and release of mode button 875 by theuser upon reaching a prime dose when reviewing the doses stored in thedose memory.

To select the dose, the user grips the cover 695 of the dial knobassembly between typically a thumb and forefinger and begins to rotateit relative to the rest of pen base 622. This rotation causescorresponding rotation of dial 680, and further barrel 700 rotatessimultaneously due to its keying with the dial. As dial 680 and the dialknob assembly rotate, they also axially translate in the proximaldirection as dial 680 screws up drive sleeve 710 due to its threadedengagement therewith. As the dial screws out, it proximally extendsfarther beyond the pen base housing, and the dial knob assembly isshifted proximally and farther away from the housing. Drive sleeve 710is held in rotatably fixed fashion by the engagement of lugs 655 withinthe housing splines. If the user rotates beyond a desired dose, the doseknob assembly and dial 680, and therefore the barrel 700, may be rotatedin the opposite direction, which operation spins the dial 680 back downthe drive sleeve 710. During this dialing down, the drive sleeve is heldin rotatably fixed fashion due to its resistance to rotationattributable 655. During the rotation of barrel 700, which is axiallystationary relative to the drive sleeve, display 871 displays acontinuously changing value of the amount of medication that pen 620would inject if operated via plunging at any given point during thatrotation. In particular, display 871 is controlled by microprocessor867, which recognizes the rotational position of barrel 700 relative todrive sleeve 710 based on input from the workings of the matrix pattern802, rings 820-825, slider assembly 838, and circuit board 865. The userhalts the dial rotation when she observes that display 871 indicates thequantity of medication desired to be injected. At this point, injectionpen 620 is configured as shown in the cross-sectional view of FIG. 25,as the cap assembly and cover 658 have previously been taken off duringthe priming step as is conventional.

The user is now prepared to inject the set dose, which injectingoperation is performed in two phases. Initially, and in the first phase,the pen is mechanically transitioned from a dosing mode to an injectingmode by proximally shifting the dose knob and dial a small distance,such as 0.080 inches of travel back into the pen housing. In particular,the user, typically with her thumb, applies a plunging force on theproximal face of dial knob cover 695. This plunging places an axial loadon dial threads 685, which loading, via the drive sleeve thread 712,advances drive sleeve assembly 708 distally within pen 620 and withoutrotation of dial 680 relative to drive sleeve assembly due to frictionalforces. This drive sleeve motion moves barrel 700 distally or forwarddue to the direct contact of the distal face of flange 716 with barrellip 705. Distal travel of dial 680, drive sleeve 701, and barrel 700 ishalted when barrel 700 reaches a location at which splines 704 mate withthe housing bulkhead splines, at which time the barrel is rotatablyfixed, and the dial, being rotatably keyed to the barrel, is alsorotatably fixed.

When pen 620 has reached this state, which is shown in FIG. 26, thesecond phase of the injecting operation begins, as any further plungingforce applied to the dial knob translates the dial knob assembly anddial 680 distally and without rotation, which translation producesrotation of drive sleeve 710. As drive sleeve 710 is rotated, theinjection clutch 762 is also caused to rotate, which forces the rotationof the injection screw 780, which due to its engagement with theinjection nut, advances the screw within the cartridge to force medicineout of the needle. As drive sleeve 710 rotates, the injection clicker754 bounces in and out of the housing splines to produce injectionclicks. The dial 680 is plunged until it reaches a plunged axialposition corresponding to the position shown in FIG. 24, at whichposition dial thread 685 abuts zero stop 713 and rotation of drivesleeve 708 is halted. During this second phase, if the injection nut 776has floated backward at all, the injection nut spring 784 finishes theinjection by moving nut 776 distally when plunging of the dial iscomplete.

During both phases of the injecting operation, microcontroller 867continuously receives the input from the electronic sensors that pick uprelative rotational motion of the barrel 700 and the drive sleeveassembly 708. Display 871, throughout the entire injection process,displays the quantity still to be injected in real time, subject to thelimitations of the electronics, which may allow the display to beupdated only, for example, eight times per second. Because the injectionswitch 853 is activated when the barrel is moved distally, themicroprocessor uses input from switch 853 to distinguish between dialinga dose and injection. The switch signal also may be used by themicroprocessor to cause the time, date and amount being injected to bestored in memory for later reference.

After injection pen 620 is used to inject the set dose, controller 867automatically returns to an off state, and the display elements ofdisplay 871 all turn off, following a certain time period of inactivity.In the event after dose setting no injection is immediately made, thedisplay remains on until the injection is made, after which the penturns off after the above-described inactivity. As the process of fullyplunging the dose setting knob assembly and dial 680 during pen useautomatically resets them, setting the dose the next time pen 620 isused simply requires rotating the dial knob assembly and dial 680 fromtheir plunged position and without further manipulation.

Microcontroller 867 can use input received from injection switch 853 andthe electronic sensors that pick up relative rotational motion of thebarrel and the drive sleeve assembly to diagnose whether the injectionpen is operating properly. For example, the pen can be programmed todisplay an error if the microcontroller senses the injection switch 853is activated while the electronic sensors are indicating that the doseis being dialed up. In addition, an error message can also becommunicated to the user via the display if the microcontroller sensesthat the injection switch 853 has not been activated, yet the input fromthe electronic sensors suggest that the dial sensing is of dubiousaccuracy, such as caused by the dial being manually rotated too rapidlyby the user.

While one particular mechanism for converting rotation of the drivesleeve into an axial motion of the cartridge piston is disclosed inFIGS. 23-27, other less complicated mechanisms known in the art, such asone in which the drive sleeve is directly threaded with a drive screw,can be substituted within the scope of the present invention.

While this invention has been shown and described as having multipledesigns, the present invention may be modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains.

1. An injection clicker assembly of a medication injector apparatus, theapparatus including a drive screw advanceable in a distal direction toshift a movable plunger of a cartridge so as to force medication from anoutlet of the cartridge, a drive sleeve of a dose injecting mechanismrotatable in a first direction within a housing of the apparatus, thedrive sleeve including a distal facing surface and defining alongitudinal bore in which the drive screw extends, and a clutchconnected to the drive screw, the clutch rotated by engagement with thedrive sleeve distal facing surface to thereby rotate and advance thedrive screw through a nut within the housing, the injection clickerassembly comprising: a collar arranged coaxially on the drive sleeve ata location proximal of the distal facing surface of the drive sleeve,said collar connected to the drive sleeve to be axially movable relativethereto and rotatably fixed thereto when the drive sleeve rotates in thefirst direction, said collar including a plurality of teeth extending inan axial direction and adapted to engage mating teeth of a stop surfaceone of integrally formed with and non-rotatably connected to a housingof the apparatus; a biasing element adapted to force said collar axiallyinto meshing engagement with said stop surface; and said collar and saidstop surface being complementarily configured such that during rotationof the drive sleeve in the first direction, and due to a returning forceapplied to said collar by said biasing element, said collar oscillatesaxially on said drive sleeve as said collar teeth slide over said stopsurface teeth to provide an audible clicking sound that indicatesinjecting use of the apparatus.
 2. The injection clicker assembly ofclaim 1 wherein said biasing element comprises a compression springarranged coaxially on the drive sleeve and having first and second ends,wherein said first end abuts a radially protruding portion of the drivesleeve, and said second end abuts said collar.
 3. The injection clickerassembly of claim 2 wherein said first end of said spring abuts aproximal side of the radially protruding portion of the drive sleeve,and wherein the distal facing surface of the drive sleeve is disposed ona distal side of the radially protruding portion of the drive sleeve. 4.The injection clicker assembly of claim 1 wherein said collar teethextend distally.
 5. The injection clicker assembly of claim 1 whereinsaid collar is keyed to the drive sleeve to be rotatably fixed thereto,and wherein said teeth of said collar and said stop surface areconfigured for unidirectional rotation, whereby meshing of the teeth ofsaid collar and said stop surface prevent rotation of the drive sleevein a direction opposite the first direction.
 6. The injection clickerassembly of claim 5 further comprising a retaining ring axially fixed tothe drive sleeve and radially projecting to limit axial motion in thedistal direction of said collar on the drive sleeve.
 7. The injectionclicker assembly of claim 6 wherein said retaining ring fits within acircumferential groove of the drive sleeve.